Wow! Never seen a set of data return such pretty statistics. I've never had 60%, 25%, 15% and 15% all in one ranking check .... that must happen only ... 15% of the time ... or maybe 25% of the time .... no, no I'm going to go for 10% ...
Actually to make it easy for people who obviously understand very well statistics but have missed one or two lesson in school here is easy explanation:
My site is back for about =/- 25 keywords to old positions (+/- 60%), for about 9-10 keywords is back to lower position. (+/- 25%) For 5-7 very import keywords is still not back. (+/- 15%)
I hope that now is a little bit more easier to understand. :)