InformationWeek: The newest Android usage figures released by Google reveal that the platform continues to be very fragmented. A majority--55 percent of users--are running Android 2.1, codenamed Eclair. Only 3.3 percent of users are on the latest version of the OS, Android 2.2 codenamed Froyo.
Older versions of the OS have many more users. Android 1.6 (Donut) has 22.1 percent, and Android 1.5 (Cupcake) has 18.9 percent of users.