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

 crash time |
     (hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        425        4.25        4.25
          1 |        356        3.56        7.81
          2 |        397        3.97       11.78
          3 |        314        3.14       14.92
          4 |        238        2.38       17.30
          5 |        302        3.02       20.32
          6 |        359        3.59       23.91
          7 |        344        3.44       27.35
          8 |        286        2.86       30.21
          9 |        283        2.83       33.04
         10 |        330        3.30       36.34
         11 |        359        3.59       39.93
         12 |        392        3.92       43.85
         13 |        428        4.28       48.13
         14 |        430        4.30       52.43
         15 |        499        4.99       57.42
         16 |        484        4.84       62.26
         17 |        518        5.18       67.44
         18 |        562        5.62       73.06
         19 |        534        5.34       78.40
         20 |        556        5.56       83.96
         21 |        570        5.70       89.66
         22 |        503        5.03       94.69
         23 |        434        4.34       99.03
         99 |         97        0.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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