Mobile advertising network Admob has unveiled its April 2010 Mobile Metrics report (http://metrics.admob.com/) and has compared unique devices running the android and iPhone Operating Systems in its network.

According to the report, the Android OS had its greatest concentration of unique devices in North America (75 percent) in April 2010, followed by Asia (12 percent) and Western Europe (11 percent). iPhone OS devices are more broadly distributed worldwide, but also had its greatest concentration in North America (49 percent), followed by Western Europe (28 percent) and Asia (14 percent).

In the US there was a 2 to 1 ratio of iPhone OS devices to Android OS devices; worldwide, that ratio expanded to 3.5 to 1. In AdMob’s network there were 8.7 million unique Android OS devices and 10.7 million unique iPhones in the United States in April 2010. But when non-phone devices running the iPhone OS – the iPod touch and iPad – are included, the number of unique devices jumps to 18.3 million in the US. Worldwide, there were 11.6 million unique Android OS devices, 27.4 million unique iPhones and 40.8 million unique iPhone OS devices.