- 1945 to 19465,477
- 1947 to 19498,375
- 1950 to 19517,524
- 1952 to 19547,670
- 1955 to 19565,942
- 1957 to 19596,982
- 1960 to 19619,081
- 1962 to 196412,779
- 1965 to 196611,359
- 1967 to 196912,360
- 19707,093
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