When I was checking my website post keyword density..... I found a strange problem. I was checking here: tools.seobook.com/general/keyword-density I found one of my post 2 word keyword density 3.29%. (28 time out of 1700 words article). Then, when i go to that post and found only 15 times(using Ctrl+f search). Then, I went my post and using same method(using Ctrl+f search) I found only 12 times keyword.(Here reduce 3 because in the editor page there was Yoast keyword setting. Thus live page reduced 3). I am not finding the other 13 or 16 keywords anywhere of the post. It is creating big headache for me. I am not using tag and category have different word. I am not using breadcrumbs too. Article plain text, image and sidebar with related post only. There was not that keyword. How can i find out those hidden keywords?