Hampden Gov Docs
C 3.134:
University Libraries owns most of the annual volumes of this Census Bureau publication, generally considered the best starting point for U.S. statistical research.

Since the official version of Stat Abs is no longer published, the ProQuest version fulfills that role.

Online & Hampden Gov Docs
C 3.134/2:H 62/789-970/
This standard census reference source is an excellent way to do longitudinal census research.