I am looking for county-level data from the U.S. containing the counties' name and FIPS code (or any other identifier) as well as information total population and urban population rates. How urban population rates are calculated, i.e. what is classified as urban and non-urban is not extremely important. More, important is that definitions are consistent.
I am looking for data for the years 1950, 1960, 1970, 1980, 1990, 2000 and 2010.
(This looks like a trivial question, and probably it is. However, I was not able to find any appropriate data when I was searching NHGIS, ICPSR etc. Maybe I overlooked something?)