JAMA reports in an article AMA Intern Med. 2019;179(11):1551-1558. doi:10.1001/jamainternmed.2019.3500 called "Association of Forced Sexual Initiation and Health Outcomes Among US Women" (particularly with regard to reproductive health, abortion, HIV or STDs etc.) The study was done with interviews of women aged 18-44 and was done in 2011-2017 with about 13 women.
The results of the stud were extrapolated to indicate that about 3 million 15 year old females (on average) were forced to have intercourse by a male about 6 years older, often with the use of drugs, threats or being held down