https://informationisbeautiful.net/beautifulnews/1208-fewer-children-dying/ #bnews
The chart starts at 1820, there were between 20-30 million births per year in that era. This compares to about 140 million per year currently. Many more babies now but that might not be the point you are making.
In 1820 there were about 5 births per woman, compared to about 2 1/2 per woman today.
World population was about 1 Billion in 1820, and around 8.1 Billion today.
Yes, it looks like it ranged from about 2.5 to 7.5 depending on how developed the country was. From the OP, we can see how many didn't make it to adulthood.
I remember my father telling about his brother Gene dying from scarlet fever when they were kids.
@SeanPLynch @individual8 @infobeautiful Gapminder had some excellent data visualisation tools that explore this information in detail: