DS1 got his first ones and 5 months, then the 4 top ones came through by 6 months. Then he didn't get more till about 8 months when I think he got another 8 in a matter of weeks. A friend of mine's daughter had nearly all her teeth by the time she was 6 months. Everyone is different.

They don't always come through in the right order either... DS didn't get the top front ones first, he got the ones next to them. He had a gap at the front like he had knocked his teeth out luckily only for a couple of weeks though.