Samantha's commercial bakery has almost cornered the market in downtown Nashville. Each month she sells 5,500 boxes of a dozen cookies for $7.50 per box and 500 cakes and pies for $40 each. Her cost to produce each cookie is $0.17 and to produce each cake or pie is $25. Her rent and other facility costs are $6,000 per month and she pays her bakery manager a salary of $42,000 per year. Samantha's variable costs are  ?  of her total revenue.