I don't know any stats Liz but I certainly have a friend who continued to BF until a month before #2 was born and in the early stages of pregnancy at least it was lots of BFing not just the odd comfort feed. The only reason she stopped was she wanted to wean number 1 before number two actually arrived - as she wasn't sure whether she could cope with tandem feeding and her oldest was only asking for an occasional feed on occasional days.