- 1872 to 18741,611
- 1875 to 18791,782
- 1880 to 18841,791
- 1885 to 18892,463
- 1890 to 18943,232
- 1895 to 18993,278
- 1900 to 19043,304
- 1905 to 19093,213
- 1910 to 19143,840
- 1915 to 19197,777
- 1920 to 19246,950
- 1925 to 19295,489
- 1930 to 19344,820
- 1935 to 19396,910
- 1940 to 19414,260
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