Daily Digit is the story behind the numbers that make the world turn. Today we're looking at life expectancy in the U.S., which has gone down for the third time in as many years. The Centers for Disease Control says the drop is directly related to the rise in opioid abuse. While the drop from 78.8 years in 2015 to 78.6 years in 2017 may see minor, it shows a startling reversal of a decades-long trend of rising life expectancy. The last time life expectancy dropped for three consecutive years was between 1916 and 1918, during one of the worst flu pandemics in modern history. The U.S. now ranks 31st in life expectancy globally, behind Costa Rica.