It is objective and seemingly unbiased by ideological viewpoints. It contains a wealth of information on Democide, by RUDOLPH J. RUMMEL, Professor Emeritus of Political Science, University of Hawaii.
Regarding your question, see Statistics Of Pre-20th Century Democide Estimates, Calculations, And Sources and these two tables especially:
Table 2.1A, lines 1-308 and Table 2.1B, lines 310-750, Pre-20th Century Democide Estimates, Sources, and Calculations