Not sure how you missed the second sentence, or why you would use made up numbers in your response when I provided the brackets.
In the U.S., as a single filer, you pay 10% on your first $9,875, 12% from $9,876 to $40,125 and 22% from $40,126 to $85,525.
It does end up at 13% of $72K, assuming the $10K standard deduction. Since only the initial percentage was posted, no one would have any way of knowing if it was coming from the total calculation or anywhere else.
