The number of people resident in Australia increased 388,100 in 2017 to June, a rise of 1.6% on 2015/16. That was far above the global increase of 1.1%, and well ahead of the United States’ gain of 0.7% and Canada’s 0.9%.
Canada and Australia seem like they will each sustain around 1% of their population. This means increasing to 350,000 people when the population increases to 35 million and then 450,000 when population increases to 45 million.
Successfully following this policy would put Canada and Australia with populations over 100 million by 2100. Both seem to be able to sustain solid economic growth and top-level per capita income.
Sustained over 100 years of high levels of immigration was the formula used by the USA to reach its population levels. The US also had higher natural population increases, but a lot more immigration was a significant factor over most of the history of the USA.
Japan and Germany’s population are shrinking and Indonesia and other emerging economies could see sustained economic growth failing.
Canada and Australia could have the fourth and fifth largest economies in the world in 2100 behind only China, India and the USA.
Canada and Australia have the land mass and resources to support advanced economies with 200 to 500 million people.
If the US were to increase immigration to 1% of existing population that would mean increasing immigration to about 3.4 million people. If 1% immigration levels were sustained for the USA, that would mean having a population around 1 billion in 2100 instead of about 500 million.