Today at the AppNation conference in San Francisco, The Nielsen Company’s Jonathan Carson, CEO, Telecom, unveiled recent research on U.S. consumers who use mobile applications.

According to Nielsen’s latest survey of mobile app downloaders, that is, consumers who have downloaded an app in the past 30 days, if you want to understand the consumer landscape for mobile apps, you have to understand the Apple iOS and Google Android ecosystems.

• Thirty-six percent of U.S. mobile consumers now have smartphones
• Consumers with Apple iOS (iPhone) and Google Android OS mobile phones represent the majority of the smartphone market in the U.S. and 74 percent of mobile app downloaders
• App downloaders with Apple iOS and Android OS smartphones have more applications on their mobile phones than those with other kinds of smartphones, with an average of 48 apps on iPhones and 35 apps on Android phones. (By comparison, app downloaders with Blackberry RIM smartphones only had an average of 15 apps on their phones.)
• They also use their apps more often: 68 percent of app downloaders with iPhones and 60 percent of those with Android phones reported using their mobile apps multiple times a day compared to 45 percent of app downloaders with Blackberry/RIM phones.