The primary question for determination here is whether the Tax Collector of Putnam County is entitled, under Code Ann. § 92-6301, to commissions on funds paid by the United States of America to Putnam County, not as taxes, but in lieu of taxes. We think not. The term “net tax digest” referred to in Code Ann. § 92-6301, contemplates and means the total amount of taxes due on all taxable property included therein. It is admitted here that the funds on which commissions were paid to the Tax Collector of Putnam County were not taxes, but were funds paid to Putnam County by the United States of America in lieu of taxes. Accordingly, such amounts were not and could not, as contended by defendant in fi. fa., be included as a part of the net tax digest. Bruce v. County of Troup, 92 Ga. App. 786 (90 SE2d 60).
Defendant in fi. fa. contends in his affidavit of illegality that said commissions paid to him were legal, proper and ap*209proved by plaintiff in fi. fa. and their attorney and that they are now estopped to allege a default. “Where the compensation of a public official is fixed by the General Assembly such public official is without authority, by express agreement or otherwise, to fix a different compensation for such public office.” Owens v. Floyd County, 96 Ga. App. 25 (99 SE2d 560). Accordingly, this contention of defendant in fi. fa. is without merit.
The plaintiff in fi. fa. seeks to recover interest at the rate of 20% per annum on the principal involved. However, Code § 89-833 provides that only 7% is legally recoverable (which the plaintiff in fi. fa. now concedes in its brief), and the affidavit of illegality was not subject to the first ground of demurrer for such reason. Therefore the trial court erred in dismissing the affidavit of illegality for this reason. However, in the, event the execution is amended within 10 days from the receipt of the remittitur by the trial court to seek only the legal interest of 7% per annum the judgment of the lower court is affirmed, otherwise reversed.
Judgment affirmed on condition.
Frankum and Jordan, JJ., concur.