J. K. Rowling sold her condominium for $500,000 on Sep- tember 14, 2006; she had paid $310,000 for it in 1998. Rowling collected the selling price as follows: 2006, $80,000; 2007, $320,000; and 2008, $100,000. Rowling ap- propriately uses the installment-sales method. Prepare a schedule to determine the gross profit for 2006, 2007, and 2008 from the installment sale.