[smallerize]

You might find it easier to dial 112, which is also universal and works outside of the USA.

[ericbarrett]

It's a much saner number, though probably easier to pocket dial as well. I'm not sure how far back it was chosen, but 112 would also dial a lot faster than 911 or 999 on a rotary phone.

[ornornor]

I think it came about around 2000.