How would I calculate contribution margin?

A B C D E F G H I L 1 Total Net Sales $ 1,875,311.00 2 Food Cost $ 798,419.00 3 sakaries and Benefits $ 774,027.00 4 Total Special Paper s 81,340.00 5 6 Location Harveys Manchu Wok Mr. Sub Pita Pit Pizza Pizza Tim Horton Unallocated 7 Percent of Total Sales 16% 12% 6% 10% 6% 20% 8 Revenue $ 307,551.00 $ 215,660.77 $ 108,768.04 $ 193,157.03 $ 114,393.97 $ 375,062.20 $ 560,717.99 9 Food Cost S 115,331.63 $ 83,676.38 $ 43,507.22 $ 79,580.70 $ 38,665.16 $ 145,524.13 $ 506,285.21 10 Salaries and Benefits 131,631.83 $ 65,560.87 $ 41,331.85 $ 84,989.09 $ 34,775.77 $ 129,771.52 11 Franchise Royalties 21,528.57 $ 10,783.04 $ 4,350.72 $ 8,692.07 $ 4,575.76 $ 26,254.35 12 Special Paper Expense 8,134.00 8,134.00 $ 8,134.00 $ 8,134.00 $ 8,134.00 $ 40,670.00 13 Contribution Margin 14