According to a Harris Poll, College Football is the third most popular American sport behind NFL and MLB. The demographic differences at the bottom are funny. Auto-racing over indexes for households with an income below $35k and in rural areas. Football under-indexes with Easterners, Liberals and Democrats. (Not trying to start a political debate, but the Eastern part is interesting in regards to Maryland and Rutgers.) College Football over-indexes with Southerners.
Big Ten teams in the Harris Poll: