Question about coinflip?

[ripwalk]

The standard "race" in poker (pair v.s. 2 overcards) is always termed a "coinflip". From various hand simulators, I've always thought the percentage for this was somewhere around the 51 to 49 percent range in favour of the pair taking it.

However, one guy I was playing tonight kept quoting the coinflip situations as being 55 to 45 in favour of the pair.

And, as I think about it, I've seen some poker broadcasts where they advertise this percentage...

I'm just wondering, what is the actually probability of the race situation in poker?