... at least in Finland, Japan, and the US.
On p. 3 of Hearn 2018:
... there is a range of evidence of decline or redirection in sexual activity from various surveys, along with somewhat greater prominence of asexualities (Carrigan et al., 2013). In some formulations, LGBTI becomes LGBTIA.
Reduction in (with-other, in-the-flesh (ITF)) sexual activity has been reported from many parts of the world, including Finland (Kontula, 2009), Japan (Haworth, 2013) and USA (Twenge et al., 2017). Such reports on sexual activity amongst young people, married couples, and older people have been framed variously as lowering of sexual desire, sex drive, sperm count and testosterone (perhaps the result not cause of reduced sexual activity (Hsu et al., 2015)), and flights from intimacy or shifts to serial monogamy.
Data from the US Center for Disease Control and Prevention indicate significant decreases in teenage sexual activity since 1988, with reported rates 22% higher then among males and 14% higher among females (Leonard, 2015). According to the Japan Family Planning Association, ‘45% of women aged 16–24 "were not interested in or despised sexual contact". More than a quarter of men felt the same way’ (Haworth, 2013).
In many parts of the world, increased time seems to be spent on looks, ‘looking good’ and self-grooming, especially by girls and young women, but also boys and young men, and older people too.
There is also growing debate on whether younger people are experiencing more depression and lower social skills, which might link with such possible changes in sexual desire and activity.