How much should be the kw density?

[danni]

you have your 3-word keyword appeared twice in your 200-word article. Then your keyword density would be,
(((32)/200)100)% that is in this case it is 3%.

The content should be Min of 500 words with 5% keyword density and should maintain keyword proximity.

If your page has 100 words content on a webpage then you can use keyword 10 times. The Keyword density is 10%

You guys should do some research before posting. KW density is irrelevant these days.