That is a rather broad time period spanning two continents. Is there a more specific time frame, group, and region you are interested in?
Statistics for this kind of question are almost impossible to throw around with any confidence. The practice of Ethnohistory is making these ideas more accessible, but there's still very little known for sure.
Ethnohistory is pairing archaeology and other disciplines with traditional historical sourcing. By doing this, you can figure out which traditional sources are best.
On a tribe-to-tribe level, in every region, there were massive disparities in family structure and population dynamics.
I can tell you one thing for certain. What looked like a fairly constant growth of native populations across the Americas was abruptly halted by European introduction. Most people assume that natural human growth patterns were experienced as Native Americans traversed the continent. After 1492, population numbers plunged towards the x-axis and never got back up off of the mat.