Keyword Density and Content Relevance are very importan on page seo factors. Your most important keyword should be present in the first and last sentence of the content. Your main keyword phrase should make up 2% – 5% of Your content. Lower Keyword Density will not make Your site appear relevant and higher keyword density might look like keyword stuffing. If You Keep Your Keyword Density between 2 and 5 Percent You should be fine. You can also check out what the other sites that are ranking well in Your niche do and adjust Your keyword density accordingly if You are looking for the optimal value.