That's not really correct. It is more like 36%. And also it is more complicated than that, as the more you earn the higher it gets, but it's roughly around 36%. The 55% is for example for secondary incomes, etc. what we call a B-kord
People on B-kort still get their deductions (Just paid back after the fiscal year is done).
You pay the 55% on:
1. salary earned on the top of the progressions hierarchy
2. When you work anonymously (Ie. you need a CPR number to get you deductions)
At a salary of ~150k USD (DKK 1m) you would pay 40% in tax - not too far away from NY or SF.