USAF Statistical Digests, 1945 through 1980, and the USAF Summary from 1976 to 1991 are available electronically.
While the USAF Statistical Digests and Summaries are not Air Force History publications, the information they contain is valuable and often requested by researchers. The statistical data has been collected, compiled and produced since 1945 by the Comptroller of the Air Force.
Earlier Digests contained a wealth of information about the USAF. Some include organization charts, leadership lists, lineage of commands, installation maps, chronologies, etc.
Be aware that categories of statistics change, as well as the starting date of the fiscal years (July through June as opposed to the now current October through September). Categories are dropped, added, and combined with others and may vary in methods of calculation throughout the years.
The electronic files available through the link below were produced by manually cutting apart and scanning existing documents; therefore, the quality varies. The Air Force History Program does not have a Digest/Summary encompassing all the years.
Army Air Forces Statistical Digest, Part I
Army Air Forces Statistical Digest, Part II
Army Air Forces Statistical Digest, Part III
USAF Statistical Digests at the Air Force Historical Studies Office.