In 1800, about 1 in 3 people lived in China.

Two men playing chess n China, 19th century

There are around 8 billion people on Earth today, and 1.4 billion of them are in China, making the country home to around 17.5% of the global population. If that seems high, consider that at the turn of the 19th century, a whopping 1 in 3 people lived in China.

Between 1700 and 1800, the population of China more than doubled. There are a few reasons for this. For one, the mortality rate went down, in part because China practiced widespread inoculation for diseases such as smallpox. Other medical technologies became more commonplace, too, including birthing techniques that reduced infant mortality.

At the same time, the global population in general was on a dramatic upswing, growing about 45% over the course of the 18th century. Still, the population growth in China far outpaced that in the rest of the world. By the year 1800, the population of China was about 300 million, and the worldwide population was, by some estimates, about 900 million (other estimates say 1 billion). That places roughly a third of Earth’s population in China at the start of the 19th century.

By the Numbers

Did you know?

Smallpox immunization goes back to the 15th century.

For thousands of years, smallpox was one of the deadliest diseases circling the globe, and it’s now been eradicated due to widespread vaccination. And while the smallpox vaccine was technically invented at the end of the 18th century, the basic concept behind it — introducing a small amount of pathogen to guard against future infection — goes back to at least 1549. At the time, a small amount of the virus, taken from the sore of an infected person, would either be scratched into someone’s skin or inhaled through their nose. It seems gross, but it worked: The disease was less fatal in people who got smallpox after inoculation.