For quite a while, thanks to the One Child Policy. The birth rate has about about 1.6 babies/woman since about 1990. It's been creeping up, but the current generation got used to the idea of one child per family. In addition, living in the cities is really expensive, and the hukou system means your kid is only guaranteed education in your hometown. I think you can often pay a fee, but I'm not sure, and in any case, it living is already expensive enough.
https://data.worldbank.org/indicator/SP.DYN.TFRT.IN?location...