tedster - 3:20 am on Jun 7, 2012 (gmt 0)
In my day to day work, I look at a lot of backlink profiles. I can't give you any "official" statement, but I can tell you that natural profiles are pretty light on matching anchor text. Any other pattern jumps out at me, and when I check with a client whose site looks like that they almost always confirm a "link building" program of some kind - and it's not chasing freely given editorial links.
The greatest proportion of natural (unarranged) backlink use something like "Company Name" or "domain name" - and then comes the whole "click here" category. I'm pretty sure that Google has dependable metrics on what percentage and variety of matching anchor text is natural.
The one exception might be for backlinks to blog articles, where an exact copy of the article's title element is a bit moew common, even in natural backlinks.
Any one backlink profile can go somewhat outside the average numbers. But if it deviates to a statistically significant degree, then you're probably courting trouble.