Yeah, 1 in 12 obviously can't be correct, or else we'd have a whole lot more murders on our hands. I think part of the problem, too, is that it isn't to know exactly how much of the US population is trans, and how many murders get reported as such.
If the average killed in the US is 20 ~ 25 a year, though, then we're off to a "great" start for 2015, and we're already up to seven so far.