How long does it take for a chick to pip?

We just had a chick that hatched tonight, it started peeping as it was still hatching.

Added: It depends on the chick. This morning I had a chick pip a small amount and now it is 4:00 in the evening. It is barely really starting to pip the egg. Another chick that was hatching this morning just came out of the shell about an hour ago. I was worried the little one didn't make it or something. But everything seems just fine.