length	success
2	93.3
3	83.1
4	74.1
5	58.9
6	54.8
7	53.1
8	46.3
9	31.8
10	33.5
11	31.6
12	25.7
13	24
14	31
15	16.8
16	13.4
17	15.9
18	17.3
19	13.6
20	15.8