keyword density should be between 2 - 3 % not more than that, less keyword density will help you a lot
The importance of KEyword Density is now over rated. The rule you should use is "What is good for the Top10 SERPs" is good for you. Match the count of the keywords and try to keep the density close to the same. The 2 to 3 % value is conservative for the body text. 5% is the max though.
All you have to do is have the keyword / keyphrase someplace on the page to substantially increase your chances (or even have a chance sometimes) of ranking for it. Rather than worrying about using the keyword a certain % of the time, instead focus on actually writing a good article. If the keyphrase is your main term, try to use it in a heading tag as well as the page title also. Keyword density is so 1995.
Wow, without knowing you instantly refuted your claim. I love these kinds of arguments. By saying "What is good for the Top10 SERPs" you imply that the ideal keyword density VARIES. And here I ask you WHY THE FUCK SHOULD IT? I guess someone at Google thought "hey, mortgage calculators should really have 1%, but Britney Spears fansites should have 5%". http://www.searchenginepeople.com/blog/how-search-really-works-the-keyword-density-myth.html Read that article and wise up. Keyword density is BULLSHIT.