Canada at 5%, NZ at 15%, even the Australian Aborigines, who had no agriculture whatsoever, have a higher proportion of the population than in the US (3% Aboriginal).
OZ and Canada even today, have near hollow interiors, with most of the populations in a thin strip. The former British Colonies were not the population draws that the US was.
In 1900, here is the total population, when natives were close to their lowest population totals
Oz 3.7M
Canada 5.3M
NZ 800k
USA 76M
Three of the four countries are similar in area
The rural midwestern state of Iowa in 1900, had 2.2M, Minnesota 1.75M, Nebraska 1M--- areas where the Natives had lived, almost the equal of all of Canada and exceed Oz
After the last of the Indian Wars were over and most Indians counted in the US census in 1890, population was 248k, with 58k 'off Reservation' and 189k 'on Reservation' across the 44 States and 4 Territories, from 295k 'on Reservation' and 44k 'off Reservation' from 1860, 339k total
Compared to NZ, Maori population was roughly 60k in 1860, to 39k in 1896, 35% drop, to US, 27% drop over the same time period