- 1892 to 18942,573
- 1895 to 18992,910
- 1900 to 19043,285
- 1905 to 19093,159
- 1910 to 19143,838
- 1915 to 19197,776
- 1920 to 19246,950
- 1925 to 19295,488
- 1930 to 19344,820
- 1935 to 19396,910
- 1940 to 19446,714
- 1945 to 194911,265
- 1950 to 195410,827
- 19554,933
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