Number of Windows 8 users ?

Im just curious what is the current number of Windows 8 users?

Ive installed Windows 8 on my 4 year old laptop and to be honest the laptop runs much faster now and the OS looks great. I was so hyped about Windows 8 that I've made a simple app (currently studying CS at University).

Ive checked the charts and imo 7000 daily downloads for a top 5 productivity app (not mine), worldwide is kinda low.

Will the OS catch up ? Is it worth developing full time for Windows store ?

Here is my app, Sticky List - Free (works on Intel and RT) incase you are interested: