gehrlekrona - 1:02 am on Jul 12, 2012 (gmt 0)

Maybe I am just dumb but had anybody figured out how to interpret the Search Queries in Webmaster Tools?
There is Queries, Impressions and Clicks. For me the Queries and Impressions vary quite a bit but the click always seems to be 10% of the impressions. Normal? I also see that if the position is not on the first page, I don't get any clicks. Normal?
The percentage for Impressions is always -39% and clicks always -19%. Compared to what?
On 7/6/12 the Impressions went up with 2500 but the clicks stayed almost the same as usual according to WMT. Funny thing is that the numbers are always an even number. If the impressions are 2500 then the clicks are 250. Rounded?
Anyway, does anybody have any insight and does it all relate to Panda and Penguin? Does Google use these numbers to for example show a lot more impressions for searches and then count the clicks and value a site that way? I am also guessing that Impressions means all places it is in the SERP for the first 1000 results since they show a lot of impressions that are all over the place.