1. Keyword density deals with the ratio of your keywords in light of the aggregate number of indexable words set in your site page. For instance, you have 100 words article, then having a 1% keyword ratio implies that you ought to have the presence of your keyword one time inside that 100 words of content.
2. Keyword Density gives a sign to the search engines that your article is about a certain particular point, which is the keyword you are focusing on. Having this sign gives your page importance and great keyword presence.
Forget keyword density nowadays. Too many algo changes! Just write naturally for your audience and then if you really want to afterwards, just incorporate your keyword somewhere toward the beginning, middle and end. Don't put much thought into keyword density - Don't sweat it!
I think #keyword density doesn't matter. Write article with your aim, what visitor want to read that all.
2-9% or 3-8% under 10%~5%
