I think 55% is a skewed, inaccurate statistic.
Here’s my theory on a trend that could heinously skew said statistic:

A guy and girl get married. Life is good. UNTIL… the guy has to drive the lame car the woman brought into the marriage, he says. “this thing sucks and it has to go”.
So they trade it in for an Xterra - the man’s idea, but since the thing is a chick magnet, of course she agrees (being a chick and all). Since they are trading in the wife’s vehicle, title has her name on it, registration (again her name) gets transferred, so although both use it, it appears as if this truck was bought by a woman, when really that’s not quite the case.

While this is quite possibly the stupidest thing I have ever posted, it actually happened to me in my first marriage. I had a 86 Integra, she had a stripped down basic Sentra.
I had to drive that thing for 2 days for some reason, and said screw this.
We sold it, and bought a used Miata. (that was about the only thing she ever thanked me for). That was “our” car, but was in her name.