- 1913 to 1914 2,668
- 1915 to 1919 7,478
- 1920 to 1924 6,652
- 1925 to 1929 5,054
- 1930 to 1934 4,077
- 1935 to 1939 5,816
- 1940 to 1944 5,462
- 1945 to 1949 10,127
- 1950 to 1954 10,151
- 1955 to 1959 7,517
- 1960 to 1960 7,875
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