Q. Where can I find time series of U.S. economic statistics?

Go to FRASER - The Federal Reserve Archival System for Economic Research, available from the St. Louis Fed.

FRASER includes:

Bank Statistics 1896-1955
Annual Statistical Digest
Banking and Monetary Statistics 1914-1970
Business Cycle Developments
Business Conditions Digest
Business Statistics (suppl. to Survey of Current Business)
Concordance of Statistics
Economic Indicators
Productivity and Costs

Also, search the BU Libraries Search for "Historical Statistics of the United States" - a few BU libraries carry this title (with various years of coverage).