Low to Highest:

Level 1 - Most common

Level 2 - 1 in 10 people

Level 3 - 1 in 100 people

Level 4 - 1 in 1,000 people

Level 5 - 1 in 10,000 people

Level 6 - 1 in 100,000 people

Level 7 - 1 in a million people

Level 8 - 1 in a billion people

Level 9 - 1 in a trillion people