The plots below represent data from 47 provinces in Switzerland collected in 1888, as the country entered a well-studied period of "demographic transition" to a lower birth rate. All developed countries passed through such a period.
The six plots represent six clusters of a conditional variable called "Agriculture", the percent of male adults who are farmers. The scale on Agriculture is percent, and the overlapping bars indicate that some provinces are shown in two plots. The plot showing the data from the provinces with the lowest percentage of men who farm is in the lower left corner.
Fertility # of live births per 1000 women of childbearing age
Agriculture % of males who are farmers
Education % education beyond primary school for draftees