A couple of weeks ago, Microsoft finally offered some official Windows 8 app numbers for the first time, stating there were over 70,000 apps available from the Windows Store. Now that the month of June has started, it looks like the number of apps in the store continues to increase at a rapid pace.
The third party MetroStore Scanner website, which offers a way to view the apps available on the Windows Store without having to have Windows 8 or RT installed, shows that there are currently 80,302 apps. That's not just a big increase from Microsoft's own numbers, it's also nearly 15,000 more than the 65,891 apps that were in the store on May 1st.
Source
A Guy