Here is a video I thought you might find interesting. http://www.youtube.com/watch?v=ihVSoVlkTGA

Price lags difficulty.. Rubish..
Difficulty goes up, price drops.
Difficulty goes up, price drops.
Difficulty goes up, price steady.
Difficulty goes up, price goes up.
See I told you it price lags difficulty.
I just didnt tell you that its meaningless or in which direction the lag occures.