The 90% comes from this article - some proper investigative journalism by the Times.
Unisex changing rooms are more dangerous for women and girls than single-sex facilities, research by The Sunday Times shows. Almost 90% of reported sexual assaults, harassment and voyeurism in swimming pool and sports-centre changing rooms happen in unisex facilities, which make up less than half the total.
Gender-neutral changing is growing as councils seek to cut staff costs and cater to transgender people. But one MP said it risked becoming a “magnet” for sex offenders and increased the danger to women and girls.
At least two-thirds of all sex incidents in public pools and leisure centres, whether inside or in the grounds, happen in unisex changing areas. Only a handful occur in single-sex changing rooms, the figures, released under freedom of information (FoI) laws, show.
...
Nicola Williams, the spokeswoman for Fair Play for Women, said “spaces where women are undressed should be single-sex as a matter of course. This is obvious, elementary safeguarding.”
The data emerged four days after Darren Johnson, a serial voyeur, was sentenced to 16 months’ imprisonment after stalking schoolgirls in the mixed changing area of Putney leisure centre in southwest London. Johnson was caught after two 14-year-olds spotted his smartphone poking through a gap from the adjoining cubicle. When police raided his house, they found 150 files of photos taken at the centre. A second voyeur, Anthony Gomes, was caught in the same unisex changing area a few weeks later.
Johnson was co-founder of the children’s soft play chain Eddie Catz, where he also filmed his staff and customers via peepholes.
There were 134 complaints of sexual misconduct in sports centre and swimming pool changing rooms last year, councils said in their FoI responses. Of these, 120 related to incidents that took place in unisex changing rooms and 14 to incidents in single-sex changing rooms. As well as voyeurism, offences recorded in unisex facilities included harassment, sexual assault and rape.
I don't find this difficult to believe at all. It's what we've been trying to tell you / common sense.
www.thetimes.co.uk/article/unisex-changing-rooms-put-women-in-danger-8lwbp8kgk