- 1930 to 19345,114
- 1935 to 19397,496
- 1940 to 19447,102
- 1945 to 194911,558
- 1950 to 195411,034
- 1955 to 19598,433
The preservation of the Duke University Libraries Digital Collections and the Duke Digital Repository programs are supported in part by the Lowell and Eileen Aptman Digital Preservation Fund