Instead of looking at keyword density, I'd look at more important metrics and factors in on site optimization.
Use moz's on on page report card http://pro.seomoz.org/tools/on-page-keyword-optimization/new to check your onpage optimization. Also, you can use the toolbar to highlight a certain keyword. I think most people nowadays don't really take keyword density into account, unless it's extremely high and the post is very spammy looking. Go for natural text that will make sense for a reader, a real human being, to read the content. Use your keywords naturally throughout the text, and I think you'll see better results than incorporating a keyword wherever possible to increase keyword density levels.