- 1905 to 19093,019
- 1910 to 19143,587
- 1915 to 19197,496
- 1920 to 19246,669
- 1925 to 19295,167
- 1930 to 19344,395
- 1935 to 19396,413
- 19402,759
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