explain in detail why this is a debit, i thought credit meant it was gonna icnrease

At ve begining of bre year, o company had an Allowance for Uacollectible Accouns of $22.200, By the end of the year, actua bod detas total $24,100 Mequired Whit is the balence of the Alownce for Uacollectibie Accounts siter the write-ofs lbefore any year-end adjusting entry)