Average return over the last 6 month compared to the current invest amount is around 11 %
6 months ago was Dec 11 2013. At that point site profit was around 8500 BTC. Now it's 18500 BTC. So profit in the last 6 months is almost exactly 10000 BTC.
The current bankroll is 50000 BTC. So the profit over the last 6 months is 20%.
How did you get 11%?
Edit: Oh I get it! Yeah, yeah. It's a terrible place to put your coins. Don't even bother - the returns are tiny. (Leave the profit for me
)