Xbox 360, PC, Wii, doesn't matter, everybody loves online user statistics. Especially when, they get into the billions, as was revealed by Microsoft's Aaron Greenberg last week.
Contributing to a Gamasutra piece on achievements, Greenberg revealed that, as of this month, there have been 2.5 billion achievements unlocked by the Xbox Live user base.
They all add up to a whopping 52 billion gamerscore points. Or, if you break that down across the install base, around 150 achievements per user.