Hello,
The Search Engines used keywords and their keyword density within the content of a web page as a very important website ranking factors – that is, the more times a particular keyword or phrase appeared in the content of a website, the more likely that the website would rank well for a search of that keyword or phrase.
Keyword Density = (Nkr / Tkn) x 100
Where:
Density = your keyword density
Nkr = how many times you repeated a specific keyword
Tkn = total words in the analyzed text