Market research firm Nielsen on Tuesday revealed the 20 most popular Android applications in the United States. Using data obtained from metered device usage as opposed to observations from surveys as most similar data is collected, Nielsen studied Android owners’ app usage over the past month. The result is a ranking of the platform’s top-20 applications by active reach, or the percentage of Android device owners who used each app within the past 30 days. Google’s Android Market topped the charts overall as well as among men and women alike, with a reach of nearly 91%. Google Maps was the second most popular app overall with a reach of 74.6%, and the app was No. 2 behind the Android Market for men with 77.1%. Gmail was third among men (75.5%), Google Search was fourth (72.4%) and Facebook rounded out the top-5 (66.9%). Among women, Facebook (81%) was second behind the Android Market, followed by Gmail (73.4%), Google Maps (71.9%) and Google Search (71.3%).