Back in 1900, the average global life expectancy was just 32 years. Oceania has recently joined Europe as the continent with the highest average life expectancy (79.1), while in Africa, the figure is 63.8. How Life Expectancy Is CalculatedThe study’s data is based on the latest figures from the CDC, which calculates its life expectancy statistics based on the age-specific death rates reported in a particular year. That means that life expectancy isn’t the same as a state or country’s death rate (i.e. Maine was the only New England state to fall below the U.S. average, with a life expectancy of 76.7 years.