In my case it was:
Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and modeling population processes. Blackwell Publishers.
In GP's case I believe they are correct the Hajnal source is not relevant to the Yangtze Basin but reading the first page should have made it clear the facts could be simultaneously true regardless where the percentages came from or if they were accurate.
Again, there are plenty of problems with the site. That it was clear these facts can't all be true simultaneously was just not one of them.
This appears to be a general introductory demography textbook. I am surprised that you looked at it and it contains specific demographic tables about marriage rates at specific time periods? Perhaps I am misunderstanding what you mean by 'I looked at one of the sources and saw it did not involve newborn rates.'
I think it might be a simple misunderstanding, but one can never be certain :).
I believe we agree we haven't seen a valid citation for "the source in which 'x' came from in 'x%'" for this stat on the site. I hope the two of us also agree this is not the point I was disagreeing with.
Where I'm currently lost is why a demography textbook, which was a different citation in the same section, must be unable to explain dead newborns need not be counted in such a statistic on the basis the textbook was not also the source of the specific percentages displayed? That'd be like saying a statistics textbook can't explain how the median can be less than the mean on the basis it wasn't also the source for the numbers displayed.