Win%=34
Loss%=66

LOSSES CONFIDENCE:
5 87.48%
6 91.73%
7 94.54%
8 96.40%
9 97.62%
10 98.43%
11 98.96%
12 99.32%
13 99.55%
14 99.70%
15 99.80%
16 99.87%
17 99.91%

Use the first 99%
Formula = 1-(Loss% ^ Losses) for excel users

example 1-(.66^12)=99.32%