By City News Service Mar 9, 2021 LOS ANGELES (CNS) - American adults without a college degree have experienced greater reductions in life expectancy when compared to their more-educated counterparts, according to a study by USC and Princeton released today. The study reveals that after nearly a century of declining mortality up to the late 1990s, the progress continued into the 21st century for more-educated Americans but stalled for the population as a whole and reversed for the two-thirds of Americans who do not have a college degree. The study, which appears in the journal Proceedings of the National Academy of Sciences, examined overall mortality in the United States using records spanning from 1990 to 2018. Assuming that mortality rates at each age remained constant at their level in each year, the researchers then calculated how long a 25-year-old could expect to live up until the age of 75.