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

 crash time |
     (hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        377        3.77        3.77
          1 |        361        3.61        7.38
          2 |        354        3.54       10.92
          3 |        255        2.55       13.47
          4 |        241        2.41       15.88
          5 |        306        3.06       18.94
          6 |        344        3.44       22.38
          7 |        355        3.55       25.93
          8 |        272        2.72       28.65
          9 |        293        2.93       31.58
         10 |        339        3.39       34.97
         11 |        383        3.83       38.80
         12 |        451        4.51       43.31
         13 |        411        4.11       47.42
         14 |        498        4.98       52.40
         15 |        538        5.38       57.78
         16 |        531        5.31       63.09
         17 |        580        5.80       68.89
         18 |        628        6.28       75.17
         19 |        510        5.10       80.27
         20 |        547        5.47       85.74
         21 |        516        5.16       90.90
         22 |        378        3.78       94.68
         23 |        428        4.28       98.96
         99 |        104        1.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016