source: https://www.cia.gov/library/publications/the-world-factbook/...
Canada is already at NPG. Italy is at 1.39.
Now on to the third world. Even Bangladesh is at 2.18, which is 1/3 of what it was in 1960. Pakistan is at 3.62, but was at 6.02 in 1990. China is at 1.56.
Most of the high birth rates are in Africa, which is approx 1/7th of the world's population. Ethiopia's is 4.40 but was 7.25 in 1990. These places also have high (infant and adult) mortality rates, which is a big reason people still have a lot of children.
Now globally... We are at 2.45, down from a peak of 5.06 in 1964, and 3.35 in 1990. And we're dropping at an average of about 0.0238 every year since 2000, which puts us at ZPG globally in 19 years.
The reason for this is simple: Human rights, a move away from subsistence farming, women's rights, access to birth control. Pushing for these things is working, and there's no reason to think that we have to implement any other plan, especially not something that leans authoritarian in any way. We just need to keep doing what we're doing, and doing it better.
Our problem then becoming a looming population crash, not overpopulation.
But that will never happen because if birth rates decrease who will support the ponzi scheme pensions? In all seriousness the resources required for the average American lifestyle and population density is sustainable. The growth rates of some developing nations are pretty terrifying though.