YANBU really but its more likely to be a lot than most.. i hope..
I don't know why its not reported, but going from my own experience, i think most of us internalise it, not wishing to upset our parents, spouse, ect. The feeling of shame sometimes of admitting that sometimes the 'abuse' doesn't feel that bad, sometimes even pleasurable (i know i'm sticking my neck out here) the threats made by the abuser, the attention is sometimes nice, the grooming, if you come from a family that doesn't give a hoot about you, you feel unloved.
You may feel like you won't be believed, that the old 'because i'm an adult and you're a child' thing. Adults, when you're little, seem to collude. Talk over you, get on well, and children are a nuisance, a pest to be left with a babysitter..
The other thing my mum used to say to me is 'I've got eyes in the back of my head' I used to look at her in wonderment trying to work out how she knew i'd had the last bit of chocolate, but later on it was 'does she know i've been abused..does she care..does she think i'm a horrible person' by the way she treated me sometimes i guess i thought as a child the answer must be yes.
Its all very complex, everyone has their own reasons for not coming forward and naming an abuser. As you get older you just protect your own children, hope it doesn't happen to them, you wouldn't discuss what had happened to you because it's locked away in the 'too painful to deal with' box, at the back of your mind. If you do, and you're like me (spoke to ExP about it and he asked 'were you provocatively dressed/acting in a certain way/flirting?' )
and after that i hid it back away.. then he used it against me in an argument.. i was a 'slag' who had slept with a married man at the age of 12 :(
I feel so sorry for women, and men, living with this and thank god for anonymity on here which enables a lot of them to talk about what has happened to them in a relatively safe and supportive environment.