Keyword frequency
Even in well-written content with a tight topical focus, the primary topical keywords are normally a small percentage of the words on the page, typically 5 to 8 percent. Because of the widespread practice of “keyword spamming” (adding hidden or gratuitous repetitions of keywords on a page to make the content seem more relevant), search engines are wary of pages where particular keywords appear with frequencies of over 10 percent of the word count. It is important to make sure your keywords appear in titles and major headings, but don’t load in meaningless repetitions of your keywords: you’ll degrade the quality of your pages and could lose search ranking because of the suspiciously high occurrence of your keywords