The Tippecanoe County Area Plan Commission collects a range of population and economic data.
U.S. Census
For census data by state, county, or down to the census block level, the best place to look is "American FactFinder" found on the U.S. Census website.
Indiana Data
For Indiana statistics, visit the Indiana Stats website for data by county. For questions regarding employment, wages, unemployment figures, etc. in the state of Indiana, go to the website for Indiana Workforce Development called Hoosiers by the Numbers.
Visit ZipSkinny for a fun comparison of several interesting statistics by zip code.