Originally Posted by lamitbore Key word selection is a very important aspect of website marketing. Online marketing has gained its popularity mainly due to the easiness of the search for the products and services.

The OP is not asking about keyword selection, rather whether keyword density affects his Google ranking - which it does. I do agree that Google sees your site as over stuffing keywords. Cut back a bit, to 2-3% and I'm sure you'll see an improvement.