Just trying to establish the time frame of the population reference --- because most assertions state the "white man" began killing off Indians after they came over by ship and appeared in the Americas.
The reality is that the majority of Indians in U.S. & Canada territory were killed by disease (not violence) - which was brought over from Europe. The second leading cause of Indian deaths were other Indian tribes. Indian tribes continually warred on one another and kept captured members of opposing tribes as slaves. Violence from white man is only third on the list.
On the subject of diseases - The diseases brought to this continent by the Europeans included bubonic plague, chicken pox, pneumonic plague, cholera, diphtheria, influenza, measles, scarlet fever, smallpox, typhus, tuberculosis, and whooping cough.
The exchange also brought New World diseases to the Old World including Syphilis, Polio, Hepatitis, and Encephalitis.
http://public.gettysburg.edu/~tshannon/hist106web/site19/diseases.htm
https://www.scientificamerican.com/article/did-columbus-bring-syphilis-to-europe/
http://www.todayifoundout.com/index.php/2014/03/native-americans-didnt-wipe-europeans-diseases/
https://en.wikipedia.org/wiki/Native_American_disease_and_epidemics