World population is estimated to reach 7.58 billion this month as World Population Day is celebrated on 11 July, but the US Census Bureau is projecting another milestone: Annual population growth will slip under 1.0% in 2020-2021 for the first time since 1950.

The United Nations declared 11 July as World Population Day in 1989, two years after world population crossed the 5 billion mark.

The Census Bureau’s International Data Base projects 2020-2021 to be the first year since 1950 where the annual population growth rate will drop below 1%. That number is expected to continue to drop.

The US Census Bureau’s International Data Base, which estimates that 7.58 billion people will be on the planet on that day, shows that world population increased by more than 50% in the 32 years since the Day of Five Billion in 1987.

From 10,000 BCE through the early 1800s, the world population stayed below 1 billion globally. By the 20^th Century, population totals soared, more than doubling between 1920 and 1980 from fewer than 2 billion people to almost 4.5 billion in 60 years.

While this growth has been rapid, annual global population growth rate actually peaked in the early 1960s at 2.2%. It has since gradually begun to decline.

While specific numbers and trends vary between and within nations, Total Fertility Rates (TFR), the average number of children a woman is expected to have, are generally dropping around the world.

Even regions that have traditionally had high population growth are showing similar trends. Their populations are still growing but at a continually slowing pace. In Malawi, for example, the TFR has been dropping for the past 10 years.

In countries such as Japan, which have long had declining rates of population growth, the TFR has been below the replacement rate of 2.1 (enough to replace the mother and father in the population) for decades.