The following data give the index numbers of 100 commodities a certain year. Form a grouped frequency distribution, takin as class-interval.
\begin{tabular}{rrrrrrrrrrr}
91 & 124 & 109 & 129 & 141 & 107 & 86 & 76 & 118 & 111 & \\
99 & 99 & 114 & 100 & 88 & 108 & 87 & 101 & 101 & 71 & \\
63 & 121 & 122 & 111 & 119 & 77 & 127 & 61 & 133 & 68 & \\
77 & 117 & 110 & 95 & 96 & 96 & 86 & 106 & 119 & 79 \\
81 & 127 & 86 & 153 & 79 & 129 & 151 & 89 & 143 & 147 \\
90 & 142 & 105 & 94 & 125 & 96 & 99 & 138 & 145 & 113 \\
129 & 87 & 113 & 110 & 144 & 91 & 106 & 104 & 97 & 115 \\
100 & 117 & 73 & 134 & 108 & 102 & 123 & 106 & 119 & 104 \\
101 & 120 & 112 & 138 & 140 & 103 & 96 & 136 & 78 & 83 \\
75 & 100 & 113 & 114 & 109 & 116 & 109 & 116 & 104 & 128
\end{tabular}
