The Windows 8 store has continued to grow apace, adding 3000 apps in the last 8 days, according to WinAppUpdate.
The total is a worldwide number, with individual markets varying in quantity. The Chinese market in particular is very robust, with more than 10,000 aps at present. It is the largest market, but unfortunately it is suspected not the one with the highest quality of apps.
At this rate the store should hit 20,000 apps before December, and will hopefully include more big-name apps by then.