It is definitely less than 10 percent of women who can ejaculate. It is often staged with urine in pornography, but that is not related to orgasm in reality. Female ejaculation is something of an urban myth. But pretty much all women, unless they have a medical problem, are capable of having orgasms.
It is more difficult for most women to get an orgasm when stimulated by intercourse, rather then clitorally. There is very little physical evidence when a woman has an orgasm -- you can't exactly show your husband proof. If you tell him it feels good, that should be all he needs to know. Normally the most physical evidence of an orgasm for a woman is vaginal muscle spasms and a slight secretion of fluid. For women, ejaculation does not signal an orgasm.
Personally, I would be a little offended if my partner told me that I didn't have an orgasm. You're the one who knows your body best.