Oscar's Incredible Eatery ($ thousands) Income Statement for the year ending December 31, 2021 Net sales 17,300 Cost of goods sold 10,600 Depreciation 3,250 Earnings before interest and taxes 3,450 Interest expense 680 Earnings before tax 2,770 Tax 940 Earnings after tax 1,830 Dividends 450 Oscar's Incredible Eatery ($ thousands) Balance Sheet as of December 31, 2021 Cash 350 Accounts payable 1,920 Accounts receivable 940 Long-term debt 3,500 Inventory 2,360 Common stock 7,500 Total current assets 3,650 Retained earnings 1,580 Net fixed assets 10,850 Total assets 14,500 Total liability & equity 14,500 Please refer to Oscar's financial statements above. What was Oscar's increase in retained earnings during 2021?