I'm just one person and my sample size is small. But judging by the number of right-leaning people I know that send me stuff from RT and other similar places, and the number of left leaning people who repeat dispiriting talking points I see in those pieces (They may never vote republican, but their enthusiasm is certainly being sapped.), I would say the percentage is quite high. That's just people being swayed like you asked, not necessarily convinced to vote or act a certain way.
Again, I'm just one person, but from what I see around me Russia and its allies are winning the propaganda war.