An estimated 108 billion people have ever lived on the planet earth.
By 1 A.D., the world may have held about 300 million people. One estimate of the population of the Roman Empire, from Spain to Asia Minor, in 14 A.D., is 45 million. However, other historians set the figure twice as high, suggesting how imprecise population estimates of early historical periods can be.
By 1650, world population rose to about 500 million, not a large increase over the 1 A.D. estimate. The average annual rate of growth was actually lower from 1 A.D. to 1650 than the rate suggested above for the 8000 B.C. to 1 A.D. period. One reason for this abnormally slow growth was the Black Death. This dreaded plague was not limited to 14th-century Europe. The epidemic may have begun about 542 A.D. in western Asia, spreading from there. It is believed that half the Byzantine Empire was destroyed in the 6th century, a total of 100 million deaths. Such large fluctuations in population size over long periods greatly compound the difficulty of estimating the number of people who have ever lived.
Assuming the population was relatively stable over the first half of the 1600s, there were about as many people in the entire world in Shakespeare’s day as there are in the NAFTA countries today.