According to data from Android apps site Androlib, 3,738,365,177 apps have been downloaded from the Android market. That’s quite an impressive number. If that number is correct that means that 125 Android apps are downloaded every second.
The last time these numbers were calculated it was 103 apps every second and 2.5 billion downloads which means that the Android users have downloaded over a billion apps in the last quarter.
At this rate the current estimate for Android downloads is 10 billion by the end of 2011.
The most up to date stats from Androlib suggest that free apps dominate paid apps in a margin of over 10/1