- 1924 to 19253,515
- 1926 to 19273,257
- 1928 to 19291,951
- 1930 to 19312,629
- 1932 to 19331,964
- 1934 to 19352,543
- 1936 to 19373,688
- 1938 to 19393,358
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