Google (NASDAQ:GOOG) Android executives reeled off several eye-popping statistics about their open-source smartphone platform at Google I/O earlier this month. Attendees learned there have been more than 100 million Android activations worldwide, with 450,000 Android developers combining to pump 200,000 applications into the Android Market. One stat Google didn't tout? How many of those apps were paid apps as opposed to simply ad-supported apps. Mobile analytics firm Distimo crunched the numbers and found that the bulk of Android developers simply aren't making a lot of money from applications they publish and sell in the Android Market. Distimo found that only two of the 72,000 paid apps in the Android Market have been downloaded more than half a million times worldwide to date. Conversely, six of the 211,000 paid iPhone apps in Apple's (NASDAQ:AAPL) App Store generate the same number of downloads from April 1 to May 19 in the United States alone. For a telling snapshot, Distimo looked at the paid games segment. Only five paid games in the Android Market sport more than 250,000 downloads worldwide, whereas 10 paid game apps in the App Store racked up more than 250,000 downloads in the United States alone in two months. This disparity, which is a big part of why Apple CEO Steve Jobs was able to report that Apple paid out $3 billion to iOS developers through March, comes despite Google's relentless efforts to overhaul, tune and tweak the Market. The platform provider has expanded carrier billing options and app payment coverage, improved search and top app listings, and fashioned an Android Market Webstore that enables users to pay for and download apps in just a couple clicks. That is not to say the efforts are all for naught, just that they aren't quite paying off the way Google may have hoped just yet. The Android Market Webstore, which boasts greater visibility for apps, should improve this issue. So why is Google lagging behind Apple? It could be a lack of exposure for key apps. Distimo said Apple refreshes its App Store's top application charts much more regularly than the Android Market. Specifically, during April alone Apple's App store for the iPhone in the United States saw  94 distinct applications with a top 10 (free or paid) position in the Apple App Store for iPhone in the United States. Conversely, there were only 26 distinct apps that reached a top 10 position in the Android Market. Meanwhile, Android Market is still rife with free app downloads. Distimo said some 96 applications have been downloaded more than 5 million times in the Android Market. Leading the free app pack is Google Maps, which happens to be the only application with more than 50 million downloads in the Android Market. Moreover, fully 20 percent of all free apps and 80 percent of all paid applications have been downloaded less than 100 times in the Android Market worldwide to date.