Sheridan Company had a 1/1/17 balance in the Allowance for Doubtful Accounts of $21000. During 2017, it wrote off $15210 of accounts and collected $4520 on accounts previously written off. The balance in Accounts Receivable was $440000 at 1/1 and $500000 at 12/31. At 12/31/17, Sheridan estimates that 6% of accounts receivable will prove to be uncollectible. What should Sheridan report as its Allowance for Doubtful Accounts at 12/31/17?