Jeez, 80+ PHs, where did all that new hardware came from!?
Just when i though that the next difficulty increase would be around 15%, this happens

The last difficulty increase was 'just' 11% (from 8000872135 to 8853416309). Bitcoin mining hardware is becoming more affordable (example: Antminer S1), no wonder that this pool and others have significant increases to their hash rate (BTC guild will reach 10 PH soon, while we are looking at 2 PH).
Cheers