Yeah, it's pretty low, especially for a male having vaginal sex with an infected female.

What was really shocking to me is that when I was growing up just as the AIDS epidemic really took off in the 80s, I was under the impression that heterosexual transmission was extremely high, to the point where if you had sex with an infected person it was basically a death sentence. When I read actual transmission statistics decades later I was surprised that they're actually that low, relatively speaking to what I thought they were before.

IIRC a lot of this came from men infected with HIV that wanted to keep the fact they have sex with other men secret, so they attributed catching it to some unnamed female prostitute, and this skewed transmission statistics in M-F sex.