Mine has darkened with age. Brown, now, with some salty streaks, but when I was younger it was reddish/blonde highlights in light brown. It still bleaches out, reddish, in the summer sun, but that just shows the gray more.
UNfortunately, I now have this fucking hole (yes, it's a fucking hole from her being in the 'top' position a lot) in the back, so I buzz it down to a quarter inch a couple of times per month.