British people are having less sex now than in recent years, according to a large national survey.
The findings, published in the British Medical Journal, suggest nearly a third of men and women have not had sex in the past month compared with around a quarter in 2001.
Less than half of men and women aged 16 to 44 have sex at least once a week, responses show. Over-25s and couples who are married or living together account for the biggest falls in sexual activity across the 21-year period.
Half of women and nearly two-thirds of men in the latest survey said they would like to have more sex.
Why the drop?
This desire for more sex was more often voiced by people who were married or living together as a couple, which the researchers say merits concern. Too busy, tired or stressed?
Lead researcher Prof Kaye Wellings said the sheer pace of modern life may be a reason why many people are having less sex.
Perhaps social pressure to over-report sexual activity may have eased, while gender equality means that women may now be less inclined to meet their partner's sexual needs irrespective of their own, say the researchers.
The decline coincides with increasing use of social media and a global recession, which may be other contributing factors.