Market research firm Newzoo said that the number of mobile gamers in the US has passed the 100 million mark, with 69 percent using smartphones and 21 percent tablets.

The company also said that 36 percent of these pay for apps, indicating that “mobile gaming is set for another year of double-digit revenue growth in the US.”

While there are some differences in gaming preferences between the US and Europe, across the board “revenue share clearly angles in favour of iOS games” – American players spend a total of five times more on iOS games than Android titles.

And across the Apple and Android ecosystems, an “astonishing” 91 percent of spend is in-app. This compares with 73 percent and 87 percent in Germany and France respectively, not including ad revenue.

Newzoo said that 19 million US gamers (28 percent of smartphone users) play on an iPhone, with an additional 18 million using an iPod Touch. In the tablet market, 12.7 million gamers (60 percent of the total) use an iPad.

In March 2012, these iOS devices generated 84 percent of revenue for the top 200 US games across the App Store and Google Play.

Newzoo said that the launch of Amazon’s Kindle Fire tablet “single-handedly doubled Android’s share of revenue in the US compared to European countries.”

“When analysing Apple’s successful monetisation, there is one dominant factor outside of differences in audience demographics and preferences: Apple requires users to connect their credit card information directly to their account, thus creating a seamless purchase experience. I can hardly imagine any other company in the world that would be able to get away with this, including Google and Microsoft,” said Peter Warman, CEO of Newzoo.

The results form part of Newzoo’s National Gamers Surveys, which involved 17,000 respondents, in combination with iOS and Android game revenue and download data, delivered in partnership with Distimo.