Consider the following table for a seven-year period: Returns U.S. Treasury Year Bills Inflation 1234567 3.55% -1.17% 3.40 -2.31 4.30 -1.21 4.72 0.63 2.52 -6.45 1.40 1.13 -9.37 -1.32 What was the average real return for Treasury bills for this time period? Note: Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16. Average real return %