- 1892 to 18942,536
- 1895 to 18992,805
- 1900 to 19043,138
- 1905 to 19093,004
- 1910 to 19143,576
- 1915 to 19197,482
- 1920 to 19246,656
- 1925 to 19295,070
- 1930 to 19344,083
- 1935 to 19395,819
- 1940 to 19445,464
- 1945 to 194910,127
- 1950 to 195410,151
- 19554,316
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