Such numbers do exist, kinda. You can go on Pubmed or Jstor and look at a whole bunch of different studies on the subject, from reputable publications, some more broad, some more narrow. If you don't want to throw a bunch of money at them in order to get through the paywall, you can use libgen and pirate those research papers. I have done so. My conclusion is that the data leaves a lot to be desired.
Two main problems:
1 - Data quality - bias/lack of evidence/small sample sizes
The most dependable data comes from medical and criminal statistics. Those are based on hard, verifiable facts. Unfortunately, the medical and criminal fields only get involved when things go wrong. Hence our most dependable numbers are also heavily skewed. Quiet, happy incest couples, for whom everything goes right, never end up in crime/medical statistics.
On the other side we have surveys. And even when those are conducted by actual scientists, they leave a lot to be desired. You either have a very small sample size that additionaly also tends to focus on only a certain population (usually students in the vicinity of the institute conductiing the study), or if you have a larger sample size, then it's pretty much guarenteed that the researchers didn't bother to talk to each participant, and it's impossible to know if the information provided was actually truthful.
2 - Comparability.
So let's say you have two good datasets and you want to aggregate them. Chances are you can't. The problem here is that the numbers in those datasets often express very different things. What is counted as incest and what isn't can vary significantly from study to study. Some count step-relations, some don't. Some count only nuclear family incest, other count other constellations too, like cousins. Some homosexual incest, others don't. Some only count penetrative sex, some count even just intimate touching.
The unfortunate truth is that if you want to get a bigger picture, and not deceive yourself, you have to do a lot of reading. Generalised incest statistics are not to be trusted in my opinion. And even if you really go through the effort and read a bunch of stuff, you only get a notion of what's going on in the real world, and not a clear picture. As long as incest remains a taboo, we will never know the full truth.