Jessica Martinez pleaded guilty to conspiring to distribute and possess with intent to distribute at least 500 grams of a methamphetamine mixture in violation of 21 U.S.C. §§ 841(a)(1), (b)(l)(A)(viii), 846, which subjected her to a 10-year minimum prison term. At sentencing, the district court1 determined an advisory Guidelines imprisonment range of 120-121 months (because of the mandatory minimum sentence), granted the government’s motion for a substantial-assistance departure, and sentenced Martinez to 90 months in prison. On appeal, Martinez’s counsel has filed a brief pursuant to Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), arguing that, in light of the assistance Martinez provided, the reduction under the departure motion should have been greater.

After United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005), the extent of the district court’s downward departure remains unreviewable on appeal, except as part of this court’s overall review of the sentence for reasonableness. See United States v. Berni, 439 F.3d 990, 992 (8th Cir. 2006) (per curiam), cert. denied, - U.S. -, 126 S.Ct. 2946, 165 L.Ed.2d 976 (2006). We conclude that Martinez’s sentence, which was below the statutory minimum and the advisory Guidelines range, is presumptively reasonable, see Rita v. United States, — U.S. -, -, 127 S.Ct. 2456, 2462, 168 L.Ed.2d 203 (2007) (approving appellate presumption of reasonableness); United States v. Harris, 493 F.3d 928, 932 (8th Cir. 2007), and we see nothing in the record to suggest that the district court misapplied the applicable sentencing factors, see Harris, 493 F.3d at 932-33. Further, after reviewing the record independently under Penson v. Ohio, 488 U.S. 75, 80, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), we have found no nonfrivolous issues for appeal. Accordingly, we grant counsel’s motion to withdraw, and we affirm.