Objective Many studies have documented higher mortality levels in the USA compared to other high-income nations. We add to this discussion by quantifying how many years behind comparison countries the USA has fallen and by identifying when US mortality rates began to diverge.

Design We use full life tables, for men and women, for 17 high-income countries including the USA. We extract the life expectancy at birth and compute the mortality rates for each 5-year age group from birth up to age 80. Using the metric of how many ‘years behind’ a country has fallen, we compare US mortality levels with those in other high-income countries (‘comparators’).

Results We report life expectancy for 17 high-income countries, for the period 1958–2007. Up to the late 1970s, US men and especially women closely tracked comparators in life expectancy. In the late 1970s in the USA, most strikingly women began to diverge from comparators so that the US female life expectancy in 2007 corresponded to that of the comparators’ average 10 years earlier. Mortality rates also began to diverge from the late 1970s, and the largest mortality gap was in the 15–49 age group, for both men and women, where the USA had fallen about 40 years behind the comparators by 2007.

Conclusions Some causes proposed for the relatively high US mortality today—racial differences, lack of universal health insurance, US exceptionalism—changed little while the mortality gap emerged and grew. This suggests that explanations for the growing gap lie elsewhere. Quantification of how many years behind the USA has fallen can help provide clues about where to look for potential causes and remedies.