In Afghanistan the birth rate is high and the death rate is decreasing; women do not work, and tend to start their families at a very young age. Life expectancy would be about 45. Most people are subsistence farmers with no family planning.

An urbanising society, with people moving into cities to work in factories; Brazil; women start working; family planning starts; living conditions and access to medicines improve. Life expectancy now up into the 60s.

An industrialised, wealthy society; the U.K.; women go to university & have careers so they're starting their families later in life; high standards of living; life expectancy is well into the 70s/early 80s.

A post-industrial society; Germany; women make a lifestyle choice to only have one child (or none); an ageing population with very high life expectancy. The death rate is higher than the birth rate.