help
When Columbus arrived in 1492, the population of Mesoamerica exceeded 25 million. Within a century after his arrival the Native population declined

until it was less than half what it had been before the arrival of Europeans.

by 90 percent.

until the influx of African slaves and Europeans replaced the native population by 1650.

before it began to grow again after Europeans introduced improved medical practices.

Question

help   
When Columbus arrived in 1492, the population of Mesoamerica exceeded 25 million. Within a century after his arrival the Native population declined 

 until it was less than half what it had been before the arrival of Europeans. 

 by 90 percent. 

 until the influx of African slaves and Europeans replaced the native population by 1650. 

 before it began to grow again after Europeans introduced improved medical practices.

anonymous · Answer

By 90 percent is the current belief.  There are extensive archaeological remains and burial grounds, particularly in the upper Midwest, that suggest a far greater population than was discovered by European explorers.  Additionally, reports by very early settlers in New England, in the 1600s, suggest a substantial recent die-off by native populations.  It has been surmised, most popularly by Jared Diamond (in "Guns, Germs and Steel") that very early European explorers accidently introduced diseases to the New World to which Europeans had long become accustomed, but which were virulent and extremely deadly to the native American populations.