- 1930 to 19313,057
- 1932 to 19332,392
- 1934 to 19352,991
- 1936 to 19374,133
- 1938 to 19393,855
- 1940 to 19414,281
- 1942 to 19433,561
- 1944 to 19454,343
- 1946 to 19475,798
- 1948 to 19496,120
- 19506,201
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