43691 races all Tracks All venues all weather all fields all distances
1st Fav 13626 31.18%
2nd 8446 19.33
3rd 6140 14.05
4th 4582 10.48
5th 3341 7.64
6th 2541 5.81
7th 1839 4.2
8th 1230 2.81
9th 787 1.8
10th 512 1.17
11th 312
12th 179
13th 85
14th 43
15th 17
16th 10
17th 1

This tells you where the 20% lies. Actually this sample puts 88.49% in the top 6