Some vital statistical ratios of demographic significance.
D000349:Africa; D000367:Age Factors; D001208:Asia; D002675:Child, Preschool; D003710:Demography; D003906:Developing Countries; D005060:Europe; D006801:Humans; D007223:Infant; D008433:Mathematics; D008875:Middle Aged; D009026:Mortality; D009656:North America; D013020:South America