This is an extremely useful tool for search engine optimization that analyzes the text content on your target webpage and calculates the density of the various words and phrases. We display the number of occurrences for each keyword, and whether those keywords were found in the page's title and description.
We also compute a weighted score for each keyword using various factors such as frequency, positioning, and placement. The keywords on your page that have the highest weights are most likely to appear in search results, while keywords with the least weight will likely not rank at all.
Please note that there is no ideal percentage for weight. However, you want your most important keywords to appear at the top of this list, and to have higher weights than less important keywords, even if it's only by a small margin. If you're struggling to rank for certain keywords, this may be why.