So, STD Risk Calculator is pretty much exactly right with their article on
HIV transmission that quotes the 1 in 10,000 figure...
By the way, there's piles more research papers, but I figured that: (a) a few dozen confirmed case reports from independent sources, (b) a list of studies showing statistically significant risk, and (c) a screenshot of what is essentially a clinic manual for medicine, current as of 2012.
And again, review what I wrote about medical risk. I am correct to say that HIV is the main risk to consider with regard to oral sex, others being gonorrhea and HSV, although different doctors might give you different answers on this. In terms of risk versus cost to treat, HIV is your main risk. Each HIV infection costs the Canadian government huge sums of money (easily more than $1 million per patient).