A restaurant has the following 12 month record of sales revenue of sales and wages costs.

Sales Revenue Wages Costs

January	$24, 500	$11,300
February	24,200	11,100
March	25,600	11,200
April	24,200	11,400
May	34,000	13, 200
June	46,200	18,600
July	53,300	21,600
August	44,000	16,100
September	34,200	15,100
October	30,400	12,800
November	28,200	11,200
December	27,000	13,000

Adjustment to the base information shown: Included in the July wages is a lump-sum retroactive wage increase of $1,800, which would not normally be part of the july wage cost. Also, in December, the restaurant catered a special Christmas function that brought in $3,400 in wages. The December wages figure also included $1,400 in Christmas bonuses to the staff. Use high-low method to calculate the restaurant's monthly fixed costs.