I'd love to know what some of these "other" areas in Minnesota, North Carolina, Texas and New Mexico call it. 
Well, if jfern had bothered to give a link, you could.
http://www.popvssoda.com/
See the "other" answers here: http://www.popvssoda.com/stats/TOTAL.html
I posted this same thing a long time ago. It's very accurate - I was probably the only person in the entire state of Michigan who called it "soda." A friend of mine came to visit last year, and he tried to order a "pop" at Taco Bell... the cashier found it so strange that he went in back to laugh with his co-workers. I think there are some parts of the midwest in which "soda" will get you seltzer. Funny stuff. 
I didn't get it from there, but yeah, that allows you to see by state. For instance, NM:
coke 386
soda 219
pop 46
soda pop 13
a large farva 5
soft drink 4
and then some joke answers
