- 1933 to 19342,162
- 1935 to 19396,413
- 1940 to 19445,957
- 1945 to 194910,453
- 1950 to 195410,185
- 1955 to 19597,553
- 1960 to 196413,430
- 1965 to 196915,459
- 1970 to 19738,936
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