Thank you for your reply. At first, I thought the same as you. However, it can't be a percentage since some of the numbers go well over 100. For example, the current chart I'm using has amounts like, 956, 824 and 540. Also, I put it to the test, and compared the coverage with the numbers, but my observations are not consistent and the numbers don't correlate. When I visit a planet and take a scan, a common lifeform like, Stratum or Tussock, usually grows near to each other and often covers the planet blue. But, the numbers are random in each system. There's no logical pattern. I'm stumped.