At one time SEOs talked about something called keyword density. The idea was that if you put just the right number of keywords in your content then you could rank it pretty well in the search engines. Then Google came along.
For awhile after Google became the dominant search engine, keyword density was still talked about widely. But links became so much more important and after about three years it became apparent to many SEOs that inbound links were just as important or more important than the number of keywords on your page. Some SEOs even start saying that the number and type of inbound links to your web pages were more important for ranking purposes.
In fact, links did become important. In many cases, you could rank a web page for its key terms by finding the right kind and right number of links with just the right anchor text. Today, however, that’s a bit more difficult to do.
Links are still important, but all the search engines are a bit less forthcoming about how links fit into the overall picture. The search engines used to report your links. Now they don’t. Not much any way. And it’s a lot more difficult to find out information about how your links are affecting your search rankings.
The way it looks now, links are still important. They’re as important as they ever were, but there are so many ranking factors now that it’s difficult to say that there is any one ranking factor that is any more important than any other. We could probably identify a dozen or so ranking factors that are at the top of the ranking factor food chain and inbound link anchor text is one of them. Still, when it comes to the number of links you need to rank for a keyword, your guess is as good as mine.