Exactly, the law excludes certain types nonconsensual sex from the definition of rape. When I got married, it was impossible in the eyes of the law for my husband to rape me and 0% of rape defendants were charged, tried or convicted of raping their wife.
For many years it was also impossible in the eyes of a law for a man to rape another man or boy. Therefore, the crime stats would have shown that 0% of rapists raped men or boys.
So, we do need to keep in mind the legal definition of rape and how it only includes certain types of nonconsensual sex. As rape currently excludes all women from being rapists (have to have that flesh and blood penis), you will automatically get 0% of convicted rapists being biological women.
In addition, the English law definition of rape isn’t the same as the definition of rape in other countries.