What was the arithmetic average return for a stock that had the following annual returns over the past 4 years: 15.00% (4 years ago), 12.00% (3 years ago), -18.00% (2 years ago), and -42.00% (last year)?(Round the value to 100th decimal and Please enter the value only without converting it to a decimal format. If the answer is 8.55%, enter 8.55)