According to the New York Times, 9% of the 1% majored in biological sciences!!
A lot of this must be because many pre meds major in a biological science. 
This would explain why 12% of the pre med category, “Health and Medical Preparatory) end up in the 1%.
The other field that comes close is money. Grouping all economics and accounting majors, 7% of them get into the 1%. Together they make up 13.5% of the uber wealthy!