13. Darren claims an eatery and needs to decide his normal income over a long- term period. After all expenses were paid, his yearly pay was as per the following: = Year 1970 1971 1972 1973 1974 1975 1976 Total for 7 years Amount = $7,150 7,335 6,520 6,600 6,600 7,025 7,810 = $49,040. Find his average yearly income