It always can get more worse...

13-07-2010    93.11%
16-07-2010    300.04%

Or sometimes it can get better...

15-08-2011    -4.40%
30-08-2011    -1.55%
13-09-2011    -1.26%
27-09-2011    -3.76%
14-10-2011    -13.09%
31-10-2011    -18.03%
14-11-2011    -0.91%
29-11-2011    -8.54%

You'll never now...

It still doesn't stop me from mining!