How do I calculate percentage on a Income Statement...?

I have 198,556.82 (100%) sales/revenue

I have 132,277.04 (66.62%) cost of goods sold

and.....66,279.78 (33.38%) gross profit



In parenthesis is the percentage of the sales but i am trying to figure out how they got this percentage based of the information above.How do I calculate percentage on a Income Statement...?
Sales is used as a denominator whereas the cost of goods sold and gross profit figures are used separately as numerators. Try it out and you will get to know how it has been done.How do I calculate percentage on a Income Statement...?
what do you want a percentage of? All together? 198556.82 is 50% of all 3 added together and divided by .50...