And because fertility rates fell across that very same period that life expectancy was going up, that pyramid that has always represented the distribution of age in the population, with many young ones at the bottom winnowed to a tiny peak of older people who make it and survive to old age, is being reshaped into a rectangle.
La pirámide que siempre ha representado la distribución de edades en la población, con muchos jóvenes en la base y que se reduce cada vez más hacia la cumbre, que representa las personas mayores que lograron sobrevivir, está tomando la forma de un rectángulo.