The number above isn't official yet, but according to Androlib, that what we're looking at right now. Their estimates are based on the 2.5 billion apps downloaded in total and number of apps added each month. Apparently, 25,000 apps were added last month, although not too many were notable. It is however interesting to see the distribution of free and paid apps in their numbers.
Regardless of the distribution of cool apps to ones that have a single purpose, none at all or just plain don't work, it shows that developers are taking an increasing interest in the Android platform. Just 2 months ago Android officially hit 100,000 apps after 2 years of existence. This and the slew of high-end devices that launched or are set to launch should see major developing houses extend their offering on Android sooner than later. We already have Angry Birds, Need for Speed and Madden NFL, as well as Pulse, Opera and Firefox, but I feel like there's more to come.
What's more interesting is the distribution of free to paid apps. Now this one's deceiving too. As you can see, more people download free apps than paid apps on average, and the most popular apps are free. However, since Google still hasn't given us a better way to pay for apps than their own Checkout platform, a good bunch of apps are free in the market but unlock full functionality only if you donate or buy licenses from the developers themselves through their websites (See Launcher Pro Plus or Titanium Backup). This metric isn't as accurate as it could be, but it is true that Android has a lot more free apps than iOS, the Blackberry market or WP7.
If you're curious what other metrics Appslib offers, hit the link here.