From the early 1990s into the early 2000s, Americans generally had sex from about 60 to 65 times a year, according to the study.
Married couples had sex an average of 56 times a year in 2014, down from 67 in 1989.
Americans work longer days, but a busy work life was actually connected with higher sexual frequency.
But more people are staying single — meaning there is less sex — and the couples who do walk down the aisle are making fewer trips into the bedroom.
Married couples generally have sex more often than single people, but that advantage is declining.
They had sex nearly 11 times during 2014, up from an average of 9.6 times in 1989.
While the decline has been nearly across the board, one group seems to be pulling everyone else down: married couples.
