0  18.0
 1   7.5
 2   5.9
 3   4.5
 4   3.7
 5   3.1
 6   3.5
 7   3.4
 8   2.9
 9   2.9
10   3.0
11   3.6
12   3.5
13   6.1
14   8.0
15  20.6