On November 1 of the current year, Rob Elliot invested $29,250 of his cash to form a corporation, GGE Enterprises Inc., in exchange for shares of common stock. No other common stock was issued during November or December. After a very successful first month of operations, the retained earnings as of November 30 were reported at $5,000. After all transactions have been entered into the accounting equation for the month of December, the ending balances for selected items on December 31 follow. On that date, the financial statements were prepared. The balance sheet reported total assets of $55,400 and total stockholders' equity of $37,250. By what amount did retained earnings increase or decrease during the period?