I have 161 images on my portfolio, and here is the breakdown for my first 3 months as a contributor at Shutterstock.
May - 92 dls - $ 30.64
June- 92 dls - $ 54.06( got my first, and only EL *)
July- 88 dls - $ 31.67
I already have 42 downloads for the month of August, the best ever for the first 10 days of the month. Shutterstock is the best agency, I got 314 downloads so far. Fotolia comes slowly in second.
* dls= downloads
* EL = Extended License for $28.00