Frequencies for phour variable in parkwork dataset :

 Crash Time |
     (Hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         56        5.59        5.59
          1 |         59        5.89       11.48
          2 |         84        8.38       19.86
          3 |         37        3.69       23.55
          4 |         30        2.99       26.55
          5 |         15        1.50       28.04
          6 |         26        2.59       30.64
          7 |         26        2.59       33.23
          8 |         30        2.99       36.23
          9 |         33        3.29       39.52
         10 |         40        3.99       43.51
         11 |         30        2.99       46.51
         12 |         32        3.19       49.70
         13 |         43        4.29       53.99
         14 |         58        5.79       59.78
         15 |         35        3.49       63.27
         16 |         42        4.19       67.47
         17 |         31        3.09       70.56
         18 |         46        4.59       75.15
         19 |         36        3.59       78.74
         20 |         60        5.99       84.73
         21 |         40        3.99       88.72
         22 |         45        4.49       93.21
         23 |         65        6.49       99.70
         99 |          3        0.30      100.00
------------+-----------------------------------
      Total |      1,002      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016