Here's an informative pie chart from the Android Developers' Blog. It details the amount of Android smartphones with each version of 'Andy's' OS. From the chart we see that now over 50% of Android phones have Froyo. Here's a breakdown of the actual numbers from the chart:
- Android 1.5 = 4.7%
- Android 1.6 = 7.9%
- Android 2.1 = 35.2%
- Android 2.2 = 51.8%
- Android 2.3 = 0.4%
Source: Android Developers