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

 crash time |
     (hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        332        3.32        3.32
          1 |        290        2.90        6.22
          2 |        327        3.27        9.49
          3 |        261        2.61       12.10
          4 |        279        2.79       14.89
          5 |        293        2.93       17.82
          6 |        325        3.25       21.07
          7 |        358        3.58       24.65
          8 |        289        2.89       27.54
          9 |        262        2.62       30.16
         10 |        366        3.66       33.82
         11 |        355        3.55       37.37
         12 |        442        4.42       41.79
         13 |        446        4.46       46.25
         14 |        501        5.01       51.26
         15 |        600        6.00       57.26
         16 |        487        4.87       62.13
         17 |        519        5.19       67.32
         18 |        585        5.85       73.17
         19 |        540        5.40       78.57
         20 |        611        6.11       84.68
         21 |        540        5.40       90.08
         22 |        478        4.78       94.86
         23 |        415        4.15       99.01
         99 |         99        0.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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