Formerly issued annually in print by the Census Bureau. That version ceased; ProQuest is compiling the data and has produced a database, which the state consortia, GALILEO added for its member institutions.
Census Bureau has historical editions, 1878 - 2012, at: http://www.census.gov/prod/www/statistical_abstract.html
All-in-one list of links to statistics by topic (Economic Conditions, Energy, etc.) -"Finding Statistics" (revised handout, spring 2011; originally presented at COMO, fall 2009)
Selected conference presentations include: