Calculate the monthly return? Use excel and round decimals answer to 2 decimal places.

Date S&P 500 Index Price ("GSPC) 1/31/1962 68.839996 2/28/1962 69.959999 3/31/1962 69.550003 4/30/1962 65.239998 5/31/1962 59.630001 6/30/1962 54.75 7/31/1962 58.23 8/31/1962 59.119999 9/30/1962 56.27 10/31/1962 56.52 11/30/1962 62.259998 12/31/1962 63.099998 1/31/1963 66.199997 2/28/1963 64.290001 3/31/1963 66.57 4/30/1963 69.800003 5/31/1963 70.800003 6/30/1963 69.370003 7/31/1963 69.129997 8/31/1963 72.5 9/30/1963 71.699997 10/31/1963 74.010002 11/30/1963 73.230003 12/31/1963 75.019997 1/31/1964 77.040001 2/29/1964 77.800003 3/31/1964 78.980003 4/30/1964 79.459999 5/31/1964 80.370003 6/30/1964 81.690002 7/31/1964 83.18 8/31/1964 81.830002 9/30/1964 84.18 10/31/1964 84.860001 11/30/1964 84.419998 12/31/1964 84.75 1/31/1965 87.559998 2/28/1965 87.43 3/31/1965 86.160004 4/30/1965 89.110001 5/31/1965 88.419998 6/30/1965 84.120003 7/31/1965 85.25 8/31/1965 87.169998 9/30/1965 89.959999 10/31/1965 92.419998 10-Year Treasury Bond Yield (ATNX) 4.1 4 3.86 3.86 3.9 4 4.04 3.96 3.94 3.92 3.92 3.85 3.87 3.94 3.95 3.95 3.96 4 4 4.02 4.07 4.15 4.08 4.14 4.15 4.18 4.23 4.22 4.19 4.15 4.19 4.21 4.18 4.16 4.2 4.21 4.19 4.22 4.2 4.21 4.23 4.2 4.22 4,27 4.35 4.41