Just a remark about birth rate *85 method: the author isn't taking into account that women are having children later. Sadly real fertility statistics are doome

Just a remark about birth rate *85 method: the author isn't taking into account that women are having children later. Sadly real fertility statistics are doomed to be late by 40 years, which is way too late, so we have to be satisfied by birthrate, but if I had to calculate the real fertility rate of a country, I would take the number of children per infertile women over 16 or something like that. Its not political, I'm not saying anybody's right or wrong, I just wanted to geek on fertility statistics