Just to make a few things clear...
1. I'm assuming that the current leaders in the uncalled districts will win.
2. I'm using figures from the 2000 census; a bit out of date I guess, but the patterns are more important for this than the actual numbers themselves.
3. I'm going to add more figures every now and again for a while. Some stuff to do with income will be up next.
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Of the 29 districts the Democrats gained...
17 have above average employment in manufacturing (with 5 having rates of manufacturing employment significantly below average).
15 have below average levels of managerial/professional occupations (with 4 having rates of these occupations significantly above average).
In 13 districts, under 25% of the population had a bachelor's degree or higher (with three districts having over 33% of the population '' '').
Interesting. So it would seem the Democratic gains were largely attributed to blue collar workers. Always good to see.