And the preface to the article explains that this is very hard to measure effectively, it is still iffy as to how comforting those numbers should be. By any measure, this is a very high risk world, simply because of the number of partners most of us have, and the frequency of the sex. And while the research cited is generally valid, one can easily increase the transmission rate to close to 100% by doing certain things with an infected partner.
So here are some rules.
If it smells bad, don't fuck it. This requires that one have sufficient knowledge to recognize the difference between the smell of normal female/male secretions and something off, but most of us should have sufficient experience.
If you have an open cut or sore, stay home. This is the most important thing, because if you have sex with someone who is infected and your blood is in contact with the infection, you can increase the frequency of transmission from these very comforting surveys 10-fold.
If you see what looks like a sore or wound on your sex partner, walk away.
If you like to do things that cut and hurt for fun, make sure they are very well protected if you then have sex (okay to get whipped on back and buttocks, then fuck, not good to clip labia or penis and draw blood then engage in any sort of sex). One of the problems with unprotected anal sex is that it tends to tear if sufficient lube and gentle patience are not used and then the fuckee's blood is exposed to whatever the fucker might have.
Get tested regularly. Asking your partners when they were last tested is not particularly helpful as the odds of getting an honest answer are only good if your partner is both clean and was recently tested, and the question can be considered a bit rude.
As for the odds of getting something from a well reviewed provider, I add one more rule of thumb - if she appears to be taking good care of herself, the odds are she is going to take good care of you. If she looks good, seems clean, does not appear inebriated, confused or otherwise weird and out of it, then she probably is okay. Common sense I guess.
I have been doing this for a while, and I admit I have not always followed those rules. There are reasons to ignore them, though not really any good ones. But at least know when you are breaking the rules, and always follow the one about getting tested, so you know ASAP when you have caught something, whether it is from simple bad luck (unlikely as that is), not paying attention to warning signs, or just doing something stupid. And when you know you have been dumb, get tested sooner.
Having said all that, if you do everything covered, no DATY, and CBJ, the odds of getting anything are very small. For every layer you remove, the odds go up, and they really jump when you do things uncovered and have a cut or open sore.
zig