Michael Holloway (Holloway) appeals from trial court’s judgment and sentence based upon a jury verdict that he was guilty of manslaughter in the first degree and robbery in the first degree. We affirm.
FACTS
The incident which gives rise to this appeal occurred on August 25 and 26,1989, in Sioux Falls, South Dakota. Holloway was eighteen years old with a history of alcohol abuse. Testimony disclosed Holloway spent the late afternoon and early evening of August 25, drinking beer and whiskey with several adult relatives and friends at his uncle’s house. Then, at about 10:30 p.m., Holloway went with relatives to the Frontier Bar where he continued to drink beer. Holloway remained in the downtown *308Sioux Falls area until approximately 2 a.m. on August 26, during which time he consumed numerous alcoholic beverages in bars and also smoked marijuana with a friend. Holloway stated that he did not remember many of the evening’s events.
The evidence at time of trial showed that the decedent, Olin Aune (Aune), who also had a history of alcohol abuse, spent the afternoon and evening of August 25, consuming numerous alcoholic beverages. Aune went to several downtown bars that evening and was refused service at the Rainbow Bar, and eventually was kicked out because of disruptive behavior.
After the bars closed, Holloway testified he began walking back toward his uncle’s house by way of a short cut behind a downtown building when Aune began yelling angrily while approaching Holloway, then pursued him into an area behind the building. The evidence presented at time of trial was that both Holloway and Aune were armed with knives. Next, a struggle ensued between them, in which Aune was stabbed and killed. Holloway remembered removing Aune’s wallet and other property from the victim’s pockets. After the incident, Holloway returned to his uncle’s house and went to bed. The victim’s body was not discovered until August 28. On August 30, Holloway’s mother and sister discovered the victim’s wallet and Holloway’s bloody jeans in the camper where he had been staying. Holloway, though not remembering many of the events which occurred on August 25 and 26, believed he was responsible and turned himself in to the police.
Holloway was tried in March, 1990. The jury returned a verdict of guilty of first-degree manslaughter and first-degree robbery, but not guilty of premeditated murder and felony murder. The judge sentenced him to one hundred twenty-one years on the manslaughter conviction, and twenty-five years on the robbery conviction to be served consecutively, for a total of one hundred forty-six years. Holloway moved for reconsideration of the sentence, which was denied by the trial court. This appeal followed.
ISSUES
1. Whether it was plain error not to instruct the jury on grand theft from the person as a necessarily included offense of robbery?
2. Whether it was plain error for the trial court to instruct on manslaughter in the first degree as a lesser included offense of murder?
3. Whether the trial court erred in refusing to instruct the jury on justifiable homicide?
4. Whether the sentence imposed by the trial court was cruel and unusual punishment in violation of the Eighth Amendment?
ANALYSIS
1) Grand Theft Instruction
Holloway was indicted for robbery in the first degree pursuant to SDCL 22-30-1 and 22-30-6.1 He argues that the trial court should have instructed the jury on grand theft as a necessarily included offense of robbery.2
The standard for instructing on lesser included offenses is well settled in *309this jurisdiction. We employ a legal test and a factual test to determine whether an offense is necessarily included within a greater offense and whether the requested instruction on the lesser offense must be given. See State v. Groves, 473 N.W.2d 456 (S.D.1991); State v. Tapio, 459 N.W.2d 406 (S.D.1990); State v. Gillespie, 445 N.W.2d 661 (S.D.1989); State v. Scholten, 445 N.W.2d 30 (S.D.1989); State v. Bonrud, 393 N.W.2d 785 (S.D.1986).
Holloway never requested an instruction on grand theft at the time of trial, and there is no record of any objection to the robbery instruction; therefore, Holloway failed to preserve any error for appeal on this issue. We have previously held when no objections were made by the defendant to any instructions of the court, and the defendant proposed no instructions, there is no question concerning the instructions before this court on appeal. Carlson v. First Nat. Bank, 429 N.W.2d 463, 465 (S.D.1988); State v. White Mountain, 332 N.W.2d 726 (S.D.1983); State v. Halverson, 87 S.D. 110, 203 N.W.2d 421 (1973).
Holloway concedes that he did not request a grand theft instruction, but he urges this court to apply the plain error rule to this issue as an alternative. We have previously stated that “the plain error rule applies only in exceptional cases, and then it must be applied cautiously; the rule does not encompass every error which occurs at trial, but only those errors which are both obvious and substantial.” See State v. Lewandowski, 463 N.W.2d 341, 344 (S.D.1990); People in Interest of R.R., 447 N.W.2d 922, 927 (S.D.1989); State v. Dombusch, 384 N.W.2d 682, 686 (S.D.1986). We fail to see how the trial court’s alleged error in failing to instruct on grand theft could be both obvious and substantial when Holloway never objected to the robbery instruction, nor requested the grand theft instruction.
We have never specifically held that grand theft is a necessarily included offense of robbery and we decline to do so now. The trial court’s duty is to instruct the jury on all matters of law which it determines are necessary for the jury to render a verdict. SDCL 23A-25-3. When jury instructions as a whole correctly state the law and inform the jury, they are deemed to be adequate. Lewandowski, supra. We find that the jury instructions given in this case satisfy the above statutory requirement and the failure to give an instruction on grand theft, even if appropriate, does not rise to the level of plain error in this case.
2) Manslaughter Instruction
Holloway asserts it was plain error for the trial court to give a manslaughter instruction. The trial court gave the instruction on manslaughter in the first degree as a lesser included offense of murder at Holloway’s request. Thus, if the court erred in giving the manslaughter instruction, it was an error which was invited by Holloway. We have previously held that invited errors are not subject to appeal. State v. Wiegers, 373 N.W.2d 1 (S.D.1985); State v. Johnson, 272 N.W.2d 304 (S.D.1978); State v. Parker, 263 N.W.2d 679 (S.D.1978). As with the grand theft instruction, we do not find this alleged error rises to the level of being so obvious and substantial as to constitute plain error. Lewandowski, supra. We accordingly hold that when counsel requests an instruction on a lesser included offense and the jury returns a verdict finding the defendant guilty of the lesser included, such trial tactics will not be a basis for a claim of plain error. If you seek and receive, you shall not claim plain error.
3) Justifiable Homicide Instruction
Holloway argues that the trial court erred when it refused to instruct the jury on justifiable homicide pursuant to SDCL 22-16-34 and 22-16-35.3 ■ State argues *310there is insufficient evidence in the record to show that Holloway was defending an attempt to commit a felony upon him or that he had reasonable grounds to apprehend a design to commit a felony. State further argues that the jury was instructed on self-defense and, therefore, considered and rejected Holloway’s claim that he was defending himself, not robbing the victim.
In order for this court to reverse, we must find that if the requested instruction had been given, the jury “might, and probably would have” returned a different verdict. State v. Willis, 370 N.W.2d 193, 200 (S.D.1985); State v. Bittner, 359 N.W.2d 121, 125 (S.D.1984). While the justifiable homicide instructions and self-defense instructions are not identical, the giving of either one would require the jury to consider whether or not it believed Holloway was defending himself against Aune. Thus, the jury was instructed on self-defense, and still convicted Holloway of manslaughter in the first degree, apparently rejecting Holloway’s claim that he was employing reasonable force to defend himself against Aune. We find ample evidence in the record to support this conviction and defeat Holloway’s claim that he was defending himself. We cannot, therefore, say that with a justifiable homicide instruction the jury “might, and probably would have,” returned a different verdict or that the trial court, after hearing all the testimony, abused its discretion in refusing to give the proposed justifiable homicide instruction. Willis, supra.
Accordingly, we hold the trial court did not err when it refused to instruct the jury on justifiable homicide.
Holloway additionally offers affidavits from several of the jurors to support his contention that the jury might have returned a different verdict had they been instructed on justifiable homicide. These affidavits do not contain any statement per-taming to alleged extraneous prejudicial information filtering into the jury deliberations, nor improper outside influence having been brought to bear upon a juror. A statute and previous cases in South Dakota prohibit jurors from impeaching their verdict absent any alleged external information or influence, thus these affidavits are excluded from consideration in this appeal. SDCL 19-14-7. Shamburger v. Behrens, 418 N.W.2d 299 (S.D.1988); State v. Luna, 378 N.W.2d 229 (S.D.1985); Buchholz v. State, 366 N.W.2d 834 (S.D.1985).
4) Sentence
Holloway contends that the trial court abused its discretion in sentencing him to one hundred twenty-one years for first-degree manslaughter and twenty-five years for first-degree robbery, and that such sentence constitutes cruel and unusual punishment in violation of the Eighth Amendment. He argues that the trial court, by sentencing him to 146 years, effectively sentenced him to life. In support of this argument, Holloway points us to numerous gratuitous statements made by the trial court at sentencing which indicate it thought the jury was too lenient.4 We have previously acknowledged that “ 'a criminal sentence must be proportionate to the crime for which the defendant has been convicted.’ ” State v. Weiker, 366 N.W.2d 823, 826 (S.D.1985) (quoting Solem v. Helm, 463 U.S. 277, 290, 103 S.Ct. 3001, 3009, 77 L.Ed.2d 637, 649 (1983)). We have also acknowledged that great deference is given to the sentencing court. Bonrud, 393 N.W.2d at 792; Weiker, 366 N.W.2d at 828.
In Weiker, we stated that “we will first determine whether a sentence ‘shocks the conscience;’ [citations omitted] or is so disproportionate to the crime so as to activate the Eighth Amendment[.]” 366 N.W.2d at 827. We also stated that we would only engage in an extensive review of the sen*311tence if we first determined the sentence was manifestly disproportionate to the crime. Id.
For the manslaughter conviction, Holloway could have received life imprisonment pursuant to SDCL 22-6-1(3), and then, pursuant to SDCL 24-15-4, he would not have been eligible for parole. Therefore, his sentence to a term of years with parole eligibility is qualitatively different from an actual life sentence. In State v. Lohnes, 344 N.W.2d 686 (S.D.1984), we recognized that a trial judge may consider parole eligibility as a factor in sentencing. Although in Lohnes, we reversed a sentence which was conditioned upon a speculative parole date, we find it distinguishable from the present case.
The basis for our reversal in Lohnes was that the defendant had accepted a plea agreement based on his understanding that if he pleaded guilty to manslaughter, he would not receive a life sentence. The trial court accepted the agreement, then sentenced Lohnes to 347 years which we found to be an effective life sentence.
In the present case, however, Holloway did not have any understanding or expectation he would be sentenced to anything less than life imprisonment. While the trial court admittedly made the improvident remarks at sentencing, its sentence was within statutory limits, reflective of the seriousness of the crime, and accounted for the mitigating circumstances of the case. Therefore, although the sentence is strict, we conclude it is proportionate to the crime.
It is settled law in this jurisdiction that absent a sentence which is so excessive in duration that it shocks the conscience of the court, a sentence which is within statutory limits is not reviewable upon appeal. State v. Swallow, 405 N.W.2d 29 (S.D.1987); State v. Andrews, 393 N.W.2d 76 (S.D.1986); State v. Janssen, 371 N.W.2d 353 (S.D.1985). We cannot say, in light of the circumstances involved in this case, that the sentence imposed shocks our conscience, nor do we find it to be so disproportionate to the crime to cause us to engage in further review.
Finally, this court held in State v. Rederth, 376 N.W.2d 579, 581 (S.D.1985), as follows:
[I]t is vital that statistics, criteria, history of cases, studies and court records be introduced at the trial court level so this Court can make an enlightened appellate review ... as to the proportionality or disproportionality under the Eighth Amendment[.]
If no record is made at the trial level, the issue is not properly preserved for appeal. State v. Sheridan, 383 N.W.2d 865 (S.D.1986); State v. Christians, 381 N.W.2d 214 (S.D.1986). The settled record and sentencing transcript contain no record of information or data regarding proportionality having been presented to the trial court for its consideration when imposing sentence. That being the case, this court will not accept an invitation to second guess the trial court on its sentence.
We affirm the trial court on all issues.
MILLER, C.J., WUEST and SABERS, JJ., concur. HENDERSON, J., concurs in part and dissents in part.. SDCL 22-30-1 provides:
Robbery defined. Robbery is the intentional taking of personal property, regardless of value, in the possession of another from his person or immediate presence, and against his will, accomplished by means of force or fear, unless the property is taken pursuant to process or otherwise pursuant to law.
SDCL 22-30-6 provides:
Degrees of robbery. Robbery when accomplished by the use of force or by putting the person robbed in fear of some immediate injury to his person is robbery in the first degree. When accomplished in any other manner, it is robbery in the second degree.
. This is pursuant to SDCL 22-30A-1 and 22-30A-17(3), which provide in pertinent part:
SDCL 22-30A-1. "Any person who takes, or exercises control over, property of another with intent to deprive him of it, is guilty of theft."
SDCL 22-30A-17. Theft is grand theft if:
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(3) Property of any value is taken from the person of another[.]
. SDCL 22-16-34 provides, in pertinent part:
"Homicide is justifiable when committed by any person when resisting any attempt to murder such person, or to commit any felony upon him[.]”
SDCL 22-16-35 provides, in pertinent part:
*310“Homicide is justifiable when committed by any person in the lawful defense of such person ... when there is reasonable ground to apprehend a design to commit a felony, or to do some great personal injury, and imminent danger of such design being accomplished.”
. Juries have the right to act irrationally or leniently. State v. Gerdes, 258 N.W.2d 839, 841 (S.D.1977).