Frequencies for first 10,000 rows of hour variable in accident dataset :

       hour |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        417        4.17        4.17
          1 |        402        4.02        8.19
          2 |        430        4.30       12.49
          3 |        337        3.37       15.86
          4 |        266        2.66       18.52
          5 |        295        2.95       21.47
          6 |        342        3.42       24.89
          7 |        293        2.93       27.82
          8 |        272        2.72       30.54
          9 |        281        2.81       33.35
         10 |        322        3.22       36.57
         11 |        360        3.60       40.17
         12 |        355        3.55       43.72
         13 |        397        3.97       47.69
         14 |        451        4.51       52.20
         15 |        493        4.93       57.13
         16 |        483        4.83       61.96
         17 |        556        5.56       67.52
         18 |        587        5.87       73.39
         19 |        545        5.45       78.84
         20 |        568        5.68       84.52
         21 |        520        5.20       89.72
         22 |        461        4.61       94.33
         23 |        437        4.37       98.70
         99 |        130        1.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016