During 2008, a construction company changed from the completed-contract method to the percentage-of-completion method for accounting purposes but not for tax purposes. The following lists include gross profit figures under both methods for the past 3 years:
Completed-Contract Percentage-of-Completion
2006 $475,000 $800,000
2007 625,000 950,000
2008 700,000 1,050,000
$1,800,000 $2,800,000
Assuming an income tax rate of 40% for all years, the affect of this accounting change on prior periods should be reported by a credit of what?