OPINION
BRAMMER, Judge.¶ 1 After a mistrial due to a hung jury, appellant Angel Diaz was tried and convicted of first-degree burglary, attempted armed robbery, and aggravated assault. Diaz asserts the trial court abused its discretion during the first trial in denying his motion for judgment of acquittal on the aggravated assault charge of which he was found guilty at his second trial. He further contends only eleven jurors participated in the determination of his guilt, violating his right to a twelve-person jury. Agreeing with his latter contention, we reverse Diaz’s convictions and remand the case for a new trial.
*211Factual and Procedural Background
¶ 2 On appeal, we view the facts in the light most favorable to sustaining Diaz’s convictions, see State v. Haight-Gyuro, 218 Ariz. 356, ¶ 2, 186 P.3d 33, 34 (App.2008), but relate here only those facts relevant to our disposition of his appeal. In July 2000, armed with a gun, Diaz forcibly entered a home occupied by an extended family and a friend of theirs. He beat one occupant, R., and demanded money from another, J. Based on this incident, a grand jury charged Diaz with possession of a prohibited weapon, first-degree burglary, attempted armed robbery of J., aggravated assault of four adults including R., and aggravated assault of two minors under the age of fifteen. After a four-day trial, a jury acquitted Diaz of both charges of aggravated assault of a minor. Because the jury was unable to reach a verdict on the remaining charges, the trial court declared a mistrial as to those.
¶ 3 A second, four-day trial was held on the remaining charges, and the jury found Diaz guilty of first-degree burglary, aggravated assault of R., and attempted armed robbery of J., all dangerous-nature offenses. The jury acquitted him of the three remaining aggravated assault charges and the weapons charge. The trial court sentenced Diaz to mitigated, concurrent terms of imprisonment totaling seven years. This appeal followed.
Discussion
Motion for judgment of acquittal
¶ 4 During his first trial, Diaz moved for a judgment of acquittal on the count charging him with the aggravated assault of R. and now asserts the court erred in denying his motion. But, because the jury was unable to reach a verdict regarding his alleged aggravated assault of R., Diaz’s first trial ended in a mistrial on that charge.1 See Ariz. R.Crim. P. 22.4. “Where the jur[ors] disagree and are discharged by the court, then the status of the case is the same as though there had been no trial at all” on the charges as to which the jurors could not agree. State v. Woodring, 95 Ariz. 84, 86, 386 P.2d 851, 852 (1963); cf. State ex rel. Sullivan v. Patterson, 64 Ariz. 40, 45, 165 P.2d 309, 312 (1946) (mistrial renders “entire proceedings ... a nullity”). Because the declaration of a mistrial had the effect of nullifying all trial proceedings related to the alleged aggravated assault of R., including those pertaining to Diaz’s motion for a judgment of acquittal, it is as if they had never happened, and there is nothing for us to review. See Woodring, 95 Ariz. at 86, 386 P.2d at 852. We, therefore, do not address the issue further.
Ttvelve-person jury
¶ 5 On the first day of the second trial, the court empaneled fifteen jurors, designating three of them as alternates. After closing arguments, the court excused the three alternates and instructed the jurors that “[a]ll 12 of you must agree on a verdict.” The twelve jurors began deliberations but did not reach a verdict before court adjourned at the end of the day. The jury reconvened the next day and resumed deliberations, but the record is silent regarding whether all twelve jurors were in attendance. When the jury returned its verdicts, the court noted “the presence of the jury” and sua sponte polled the jury, confirming the polled jurors agreed with the verdicts the foreperson had delivered. According to the trial transcripts, however, only eleven jurors were polled.
¶ 6 Diaz asserts all twelve jurors did not participate in the determination of his guilt, resulting in fundamental error. Because he did not raise this argument in the trial court, we review it only for fundamental, prejudicial error. See State v. Henderson, 210 Ariz. 561, ¶¶ 19-20, 115 P.3d 601, 607 (2005); State v. Price, 218 Ariz. 311, ¶ 10, 183 P.3d 1279, 1282 (App.2008). In fundamental error review, the defendant bears the burden of persuasion and must first establish that an error occurred. See Henderson, 210 Ariz. 561, ¶¶ 19-20, 23, 115 P.3d at 607, 608. A defendant fails to meet his burden to prove error when “the record on appeal contains evidence that reasonably supports a finding” *212that no error occurred. State v. Avila, 217 Ariz. 97, ¶ 12, 170 P.3d 706, 709 (App.2007). If the defendant succeeds in establishing error, he must also prove the error was fundamental and prejudiced him. See Henderson, 210 Ariz. 561, ¶¶ 19-20, 115 P.3d at 607.
¶ 7 “It is well-settled that a 12-person jury is required if a defendant’s cumulative possible sentence totals 30 years or more.” State v. Luque, 171 Ariz. 198, 200, 829 P.2d 1244, 1246 (App.1992); see Ariz. Const, art. II, § 23; A.R.S. § 21-102(A); State v. Henley, 141 Ariz. 465, 469, 687 P.2d 1220, 1224 (1984). Conviction based on a finding of guilt by fewer than the twelve jurors to which a defendant is entitled constitutes fundamental, prejudicial error. Price, 218 Ariz. 311, ¶ 10, 183 P.3d at 1282; see Henley, 141 Ariz. at 469, 687 P.2d at 1224. When such error has occurred, we must remand the case for a new trial on the charges of which the defendant was convicted “to vindicate his constitutional right” to a twelve-person jury. State v. Pope, 192 Ariz. 119, ¶ 12, 961 P.2d 1067, 1069 (App.1998); see Henley, 141 Ariz. at 469, 687 P.2d at 1224.
¶ 8 The state concedes Diaz was entitled to a twelve-person jury.2 Nonetheless, it contends that, although the trial court polled only eleven jurors, “[Diaz] was unanimously found guilty by a 12-person jury.” In support of its contention, the state points out that “twelve jurors retired to deliberate” on the third day of trial. When the jury returned its verdicts the following day, the court noted “the presence of the jury,” and the polled jurors each confirmed they agreed with the verdicts. The state further argues that, had only eleven jurors delivered the verdicts the following day, “one would expect someone among the eleven jurors, defense counsel, [Diaz], the prosecutor, the judge, the eom't clerk, the bailiff, and the court reporter to have noticed and questioned the absence of one of the jurors.” Thus, the state reasons, the record does not suggest Diaz’s right to a twelve-person jury was compromised but, rather, merely reflects the court reporter’s “failure to refeord] the polling of one juror.” Relying on State v. Greer, 190 Ariz. 378, 948 P.2d 995 (App.1997), the state concludes such an error is harmless.
¶ 9 The state’s reliance on Greer is misplaced, however. In Greer; the court reporter had failed to transcribe the answers of each juror as he or she was polled, instead merely noting parenthetically that the jury had been polled. 190 Ariz. at 380, 948 P.2d at 997. On appeal, the defendant argued the omission from the transcript had deprived him of his right to poll the jury. Id.; see Ariz. R.Crim. P. 23.4. Division One of this court affirmed Greer’s convictions, finding the omission harmless because the trial court’s minute entry “adequately] ree-ord[ed]” that the court had polled the jury and that the jurors had confirmed the unanimity of the verdict. Greer, 190 Ariz. at 381, 948 P.2d at 998.
¶ 10 The defendant in Greer did not dispute that a full jury had participated in the determination of his guilt. 190 Ariz. at 380-81, 948 P.2d at 997-98. Rather, Greer merely contended the failure to transcribe the polling procedure deprived him of his right to poll the jury to confirm the unanimity of the verdict. Id. That, of course, is not the ease here; whether all twelve jurors participated in deliberating and determining his guilt is the crux of Diaz’s argument. The state’s attempt to analogize this ease to Greer rests on the premise that twelve jurors were, in fact, present and that the transcript, therefore, merely reflects the court reporter’s failure, as in Gr-eer, to accurately record the polling of the jury.
¶ 11 On the record before us, however, we cannot conclude all twelve jurors participated in the determination of Diaz’s guilt. At the outset, we must view the record on appeal and all reasonable inferences therefrom in the light most favorable to sustaining Diaz’s convictions. See State v. Hassman, 101 Ariz. 583, 583, 422 P.2d 699, *213699 (1967). When portions of the record are missing on appeal, we presume the missing portions support the trial court’s actions. See State v. Printz, 125 Ariz. 300, 304, 609 P.2d 570, 574 (1980). But, when all portions of the record are accounted for, we presume the record accurately reflects the proceedings in the trial court. See State v. Anders, 1 Ariz.App. 181, 184, 400 P.2d 852, 855 (1965); cf. Palmer v. Superior Court, 114 Ariz. 279, 280, 560 P.2d 797, 798 (1977) (“The record in a court of record is the highest evidence of what was done and it is conclusive unless attacked for fraud.”). We generally will presume no error has occurred and that the jury followed all instructions the trial court gave it in the absence of any suggestion in the record to the contrary. See State v. Ramirez, 178 Ariz. 116, 127, 871 P.2d 237, 248 (1994); State v. Saiz, 3 Ariz.App. 223, 225, 413 P.2d 282, 284 (1966). However, we may not indulge in presumptions or inferences wholly contradicted by the record.
¶ 12 In this case, the record is not silent regarding the error Diaz alleges— the transcript of the jury poll reflects that only eleven jurors determined his guilt. See Saiz, 3 Ariz.App. at 225, 413 P.2d at 284. No portions of the record are missing, nor do other facts appear in the record from which we could reasonably infer that all twelve jurors, in fact, returned the verdicts. See Anders, 1 Ariz.App. at 184, 400 P.2d at 855. Although the record indicates twelve jurors retired to deliberate on the third day of trial, nothing other than the jury poll indicates how many jurors returned to deliberate and render the verdicts the following day. Indeed, the jury polling, an event that occurs immediately after the jury has concluded its deliberations and returned a verdict, may often be the only direct evidence informing a reviewing court whether a defendant was found guilty by the required number of jurors, because “one important purpose served by conducting a poll is to assure there is a sufficient number of jurors expressing them individual agreement with the verdict, as read in court, to render the verdict valid.” Sandford v. Chevrolet Div. of Gen. Motors, 52 Or.App. 579, 629 P.2d 407, 411 (1981), aff'd, 292 Or. 590, 642 P.2d 624, 637 (1982) (confirming jury poll “designed to test the numerical validity of a verdict”); see Ariz. Const. art. II, § 23; § 21-102(A). In Sand-ford,, the Oregon Court of Appeals noted that the source of a party’s right to poll the jury was Rule 59(G)(3) of the Oregon Rules of Civil Procedure, see 629 P.2d at 411, a rule substantively similar to Arizona’s rules providing for jury polling in both criminal and civil eases. See Ariz. R.Crim. P. 23.4; Ariz. R. Civ. P. 49(f). In civil cases in Arizona where the verdict is not unanimous, each juror agreeing with the verdict must sign it, Ariz. R. Civ. P. 49(a), a procedure that serves much the same purpose as the jury poll. See United States v. Causor-Serrato, 56 F.Supp.2d. 1092, 1094-95 (N.D.Iowa 1999). As is true for jurors in civil actions in Oregon, each juror in a criminal case in Arizona is not required to sign the verdict; therefore, the jury poll is the only formal mechanism for confirming that the required number of jurors rendered it. See Or. R. Civ. P. 59; Ariz. R.Crim. P. 23.1(a). Further, because only the jury foreperson signs the verdict, polling the jury also serves to confirm each individual juror’s assent to the verdict. See State v. Kiper, 181 Ariz. 62, 68, 887 P.2d 592, 598 (App.1994).
¶ 13 Contrary to the state’s and the dissent’s assertion, the facts that the trial court noted the presence of “the jury” on the day it resumed deliberations and reached its verdicts and that the polled jurors affirmed their verdicts were unanimous say nothing about the number of jurors present. Nor do they contradict the transcript’s statement that “the jury” returning the verdicts consisted of the eleven jurors polled. Despite the dissent’s suggestion to the contrary, we may not presume the jurors followed the court's instruction that all twelve of them must decide and deliver the verdicts, because the record contains “some evidence to the contrary.” Ramirez, 178 Ariz. at 127, 871 P.2d at 248 (presumption jury followed instructions overcome by facts in record suggesting otherwise).
¶ 14 In the face of a transcript showing-only eleven jurors determined Diaz’s guilt, and in the absence of other facts supporting the inferences that twelve jurors actually participated in that determination and that *214the transcript merely reflects a polling error or an inadvertent omission by the court reporter, we cannot conclude “the record on appeal contains evidence that reasonably supports a finding” that twelve jurors delivered the verdicts here.3 Avila, 217 Ariz. 97, ¶ 12, 170 P.3d at 709. Nor may we accept the state’s invitation to conclude, despite the clear record, that twelve jurors must have determined Diaz’s guilt because, had only eleven returned the verdicts, surely someone present would have raised the issue immediately. To indulge in such speculation would undermine the presumption of the record’s accuracy based solely on our intuitive incredulity that such an error could have occurred. See Anders, 1 Ariz.App. at 184, 400 P.2d at 855; cf. Nelson v. Indus. Comm’n, 134 Ariz. 369, 376, 656 P.2d 1230, 1237 (1982) (“Reasonable inferences from the [record] will be supported, but speculation based on nothing in the record cannot be indulged.”). Furthermore, although we are troubled by the fact the trial court might have been able to resolve the question before us had Diaz, or anyone else, raised it below, to conclude that no error occurred simply because no one raised the issue below would obviate all need for fundamental error review. See Price, 218 Ariz. 311, ¶ 10, 183 P.3d at 1282 (when issue not raised in trial court, we review for fundamental error whether defendant denied right to twelve-person jury).
¶ 15 Because we must presume the accuracy of the record on appeal, see Anders, 1 Ariz.App. at 184, 400 P.2d at 855, and because the denial of Diaz’s right to a twelve-person jury constitutes fundamental, prejudicial error, we reverse Diaz’s convictions of first-degree burglary, aggravated assault of R., and attempted armed robbery of J., and remand the ease for a new trial on those charges.4 See Price, 218 Ariz. 311, ¶ 10, 183 P.3d at 1282; Henley, 141 Ariz. at 469, 687 P.2d at 1224.
CONCURRING: PETER J. ECKERSTROM, Presiding Judge.. Diaz does not contend the trial court erred in declaring the mistrial.
. In his second trial, Diaz faced charges of first-degree burglary, attempted armed robbery, possession of a prohibited weapon, and four counts of aggravated assault with a deadly weapon. The aggravated assault charges alone exposed Diaz to a possible sentence totaling sixty years' imprisonment. See A.R.S. § 13 — 1204(A)(2) and (B); 2008 Ariz. Sess. Laws, ch. 24, § 1; see also A.R.S. § 13-116.
. We emphasize that we cannot assume, when the only evidence in the record suggests the contrary, that the error was merely one of incomplete polling or an inaccurate transcript. To presume such irregularity would be contrary to our presumption of the record’s accuracy and inconsistent with an orderly functioning judiciary. See Anders, 1 Ariz.App. at 184, 400 P.2d at 855; cf. Palmer, 114 Ariz. at 280, 560 P.2d at 798.
. We do not vacate the jury's verdicts acquitting Diaz of three aggravated assaults and possession of a prohibited weapon because, unlike conviction based on a finding of guilt by less than twelve jurors, acquittal by less than twelve jurors, although error, does not prejudice the defendant. See Henley, 141 Ariz. at 468-69, 687 P.2d at 1223-24 (reversal required only " 'where the fundamental error harms the defendant’ ”), quoting State v. Sorrell, 132 Ariz. 328, 329, 645 P.2d 1242, 1243 (1982); see also Henderson, 210 Ariz. 561, ¶ 20, 115 P.3d at 607. The state, moreover, did not raise this issue in the trial court or on appeal.