Hallo, sorry für Englisch, mein Deutsch ist schlecht...
I did a complex research of Czech WordPress environment last month (unfortunately just before a wave of updates). I found and analyzed 65,000 WP sites and tried to determine their versions, used themes and plugins and many more.
Because we are neighbours, I think you may be interested how it (doesn't) work in the Czech Republic. Data are related to the our country, but I think that situation is very similar in other coutries.
Article: http://lynt.cz/blog/wordpress-in-the-czech-complex-research