(HealthDayNews) -- You've come a long way, baby, and most of it happened in the 20th century.
The average life span for a caveman was 18 years, says Amazing Facts About Your Body, a book published by Doubleday and Co.
The life span for the ancient Romans averaged only 22 years. In the 1,850 years after the Roman Empire, human lives were extended little more than a year per century, reaching an average life span of 37 by the mid-19th century.
While it took 4 million years to double the average human life span the first time (from caveman to the 19th century), the next doubling took less than 150 years. We advanced from 37 in 1850 to well over 70 years in developed countries today.
