Velti, a provider of mobile marketing and advertising technology, released its September "State of Mobile Advertising" report, which shows that iOS gained a 5% market share lead over Android and now accounts for 62% of mobile ad impressions (compared to Android’s 38%).

Velti also reports that just under half of all iPhone 5 impressions came from the U.S., followed by Japan with 14% , and the UK with eight percent of impressions. Additionally, Velti data reveals that, although iOS 6 saw quick adoption among a large amount of users, 11% of users have opted not to upgrade to the operating system and remain using iOS 4.

"In July and August, Android held prevalent market share in a year that was previously dominated by iOS -- but September marks an end to this trend," says Krishna Subramanian, CMO of Velti. "We are seeing a pattern that leads us to believe the shift back to iOS domination is a result of the iOS 6 release and iPhone 5 launch. In fact, this is similar to the change we saw directly after the iPhone 4S release, when iOS volume also spiked by 5%."

Velti’s September report also reveals insight into engagement patterns of iPhone 5 early adopters. Consumers were eager to try out their favorite apps on their new devices. Velti’s data shows consumers spent 27% of their time on social networking applications, followed by games (22%) and entertainment and utility apps (13 percent%).

Despite Apple’s prevalence in the U.S. and excitement around the iPhone 5 launch, other regions are not necessarily following suit. The new Velti data shows that Samsung is the clear leader in its home market of Korea, and it is the #1 smartphone, with a sizeable margin, in impression share there. Apple’s devices are relegated to the third and fifth places in the country (iPhone 3 and iPhone 4 respectively). Other notable data from the report includes:

° Samsung’s Galaxy S III: Samsung’s Galaxy S III entered the top five devices on the exchange this month, capturing 1% of all impressions.

° AT&T leads U.S. carriers with over half of all iPhone impressions. Verizon comes in second with just under a third of impression volume.

Data for this report is taken from the Mobclix Exchange, which sits at the intersection of 33,500+ apps and 45+ ad networks. To download the full report, please visit www.velti.com/data_reports.html .