You need a solid mix of ******** and nofollow links pointing to your site. I have heard that a 60%/40% ratio (********/nofollow) is a good, natural backlink strategy to follow. Otherwise, Google's algorithm could penalize you for too many ******** links and lower your SERPs ranking.
they really expect you to have nofollow backlinks? 40% seems like a lot. I would expect much more to be follow naturally.