It is possible that the 90 % refers to the total amount paid by a particular group. It is possible for the highest tax rate to be only 50% and that group in the bracket to pay a much higher percentage of the total amount.
However, the challenge with balancing the budget by "taxing the 1%" is that there are (by definition) too few of them.
It seems that they paid 37 % of taxes and the top 10 % paid 70 % of taxes. Not 90 % but once Faith said 90 % we knew it was wrong because she hasn't had a right number ever.
You'd have to define "twerps" before you could calculate the amount they pay.