Frequencies for phour variable in parkwork dataset :

 crash time |
     (hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         62        5.68        5.68
          1 |         56        5.13       10.82
          2 |         90        8.25       19.07
          3 |         46        4.22       23.28
          4 |         27        2.47       25.76
          5 |         45        4.12       29.88
          6 |         31        2.84       32.72
          7 |         25        2.29       35.01
          8 |         32        2.93       37.95
          9 |         42        3.85       41.80
         10 |         32        2.93       44.73
         11 |         46        4.22       48.95
         12 |         48        4.40       53.35
         13 |         59        5.41       58.75
         14 |         53        4.86       63.61
         15 |         50        4.58       68.19
         16 |         38        3.48       71.68
         17 |         41        3.76       75.44
         18 |         50        4.58       80.02
         19 |         39        3.57       83.59
         20 |         36        3.30       86.89
         21 |         49        4.49       91.38
         22 |         41        3.76       95.14
         23 |         51        4.67       99.82
         99 |          2        0.18      100.00
------------+-----------------------------------
      Total |      1,091      100.00

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