Pretty substantial numbers to me....
http://www.earlyamerica.com/review/2007_summer_fall/native-americans-smallpox.html
"This Native American depopulation occurred during the contact period, causing the Native American population size to decline from 1-18 million before European contact (c. AD 1500) to an
estimated 530,000 by 1900."
http://www.planeta.com/ecotravel/mexico/yucatan/tales/0303yucatan.html
As a bit of background, Spanish invaders battled 19 years to conquer the Maya in the Yucatán Peninsula. Unlike the Aztecs in central Mexico who succumbed to Cortez in less than two years, the Mayans were not easily overtaken. But by 1700, a once robust Maya population had fallen to 150,000 due to disease, displacement and famine