Frequencies for phour variable in parkwork dataset :

 Crash Time |
     (Hour) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         46        4.32        4.32
          1 |         78        7.33       11.65
          2 |         88        8.27       19.92
          3 |         32        3.01       22.93
          4 |         43        4.04       26.97
          5 |         45        4.23       31.20
          6 |         34        3.20       34.40
          7 |         31        2.91       37.31
          8 |         27        2.54       39.85
          9 |         19        1.79       41.64
         10 |         42        3.95       45.58
         11 |         39        3.67       49.25
         12 |         39        3.67       52.91
         13 |         59        5.55       58.46
         14 |         26        2.44       60.90
         15 |         41        3.85       64.76
         16 |         44        4.14       68.89
         17 |         46        4.32       73.21
         18 |         37        3.48       76.69
         19 |         36        3.38       80.08
         20 |         41        3.85       83.93
         21 |         53        4.98       88.91
         22 |         51        4.79       93.70
         23 |         66        6.20       99.91
         99 |          1        0.09      100.00
------------+-----------------------------------
      Total |      1,064      100.00

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