- 19142,839
- 1915 to 19197,951
- 1920 to 19247,133
- 1925 to 19295,761
- 1930 to 19345,112
- 1935 to 19397,495
- 1940 to 19447,101
- 1945 to 194911,557
- 1950 to 195411,033
- 1955 to 19598,432
- 1960 to 196414,158
- 1965 to 196916,168
- 1970 to 19728,831
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