By my count, I should only have 7. 1 for activating Shift, 1 from a code on Facebook, 1 from a code on Twitter, 1 from another code, and 3 for activating Shift in Aliens: Colonial Marines. That's 7. Don't know how I got the other 7, but you won't see me complain about it. XD
Some codes activated 5 keys. If you used 2 of those codes and used 1 key, then you'd have 14 left. The Shift menu shows how many of each code type (1 key from Facebook, 1 key from Twitter, 5 key, etc.) you've used.