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

 crash time |
     (hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        409        4.09        4.09
          1 |        423        4.23        8.32
          2 |        415        4.15       12.47
          3 |        316        3.16       15.63
          4 |        259        2.59       18.22
          5 |        289        2.89       21.11
          6 |        371        3.71       24.82
          7 |        316        3.16       27.98
          8 |        273        2.73       30.71
          9 |        276        2.76       33.47
         10 |        314        3.14       36.61
         11 |        338        3.38       39.99
         12 |        403        4.03       44.02
         13 |        392        3.92       47.94
         14 |        444        4.44       52.38
         15 |        479        4.79       57.17
         16 |        495        4.95       62.12
         17 |        563        5.63       67.75
         18 |        598        5.98       73.73
         19 |        557        5.57       79.30
         20 |        543        5.43       84.73
         21 |        542        5.42       90.15
         22 |        423        4.23       94.38
         23 |        460        4.60       98.98
         99 |        102        1.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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