SEO: Keyword Density does it matter?

Keywords
We dont pay too much attention to keyword density and certainly dont write webcopy to meet a percentage quota for certain search terms as we believe naturally written text is the best webcopy for a site, but there is a great feature in Google Webmaster tools whereby you can see the most popular search terms / keywords that the Googlebot found when crawling your site.
Its important to review these to ensure that they reflect the subject matter of your site. The sample below would be a good example of a Scuba Instructor Education Center.
The higher the percentage the more occurrences of that word there are in your site, variants show the different words that ‘count’ for the same core word, for example the variants encountered for course are ‘course’ and ‘courses’.
Position Keyword Significance
1. padi (2 variants) 100%
2. course (2 variants) 88%
3. instructor (2 variants) 81%
4. idc (2 variants) 69%
5. dive (4 variants) 66%
6. diver (2 variants) 52%
7. diving 34%
8. water (2 variants) 25%
9. scuba 25%
10. specialty (2 variants) 12%
11. eanx 10%
12. care 10%
13. schedule (2 variants) 10%
14. divemaster (2 variants) 9%
15. education (2 variants) 9%
16. continue (3 variants) 8%
17. package (2 variants) 8%
18. florida 7%