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

 crash time |
     (hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        405        4.05        4.05
          1 |        311        3.11        7.16
          2 |        379        3.79       10.95
          3 |        221        2.21       13.16
          4 |        254        2.54       15.70
          5 |        307        3.07       18.77
          6 |        333        3.33       22.10
          7 |        368        3.68       25.78
          8 |        265        2.65       28.43
          9 |        255        2.55       30.98
         10 |        264        2.64       33.62
         11 |        355        3.55       37.17
         12 |        452        4.52       41.69
         13 |        398        3.98       45.67
         14 |        431        4.31       49.98
         15 |        473        4.73       54.71
         16 |        484        4.84       59.55
         17 |        701        7.01       66.56
         18 |        724        7.24       73.80
         19 |        582        5.82       79.62
         20 |        544        5.44       85.06
         21 |        506        5.06       90.12
         22 |        498        4.98       95.10
         23 |        398        3.98       99.08
         99 |         92        0.92      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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