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

       hour |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        349        3.49        3.49
          1 |        421        4.21        7.70
          2 |        365        3.65       11.35
          3 |        261        2.61       13.96
          4 |        227        2.27       16.23
          5 |        243        2.43       18.66
          6 |        347        3.47       22.13
          7 |        361        3.61       25.74
          8 |        287        2.87       28.61
          9 |        287        2.87       31.48
         10 |        320        3.20       34.68
         11 |        339        3.39       38.07
         12 |        397        3.97       42.04
         13 |        438        4.38       46.42
         14 |        491        4.91       51.33
         15 |        561        5.61       56.94
         16 |        494        4.94       61.88
         17 |        510        5.10       66.98
         18 |        640        6.40       73.38
         19 |        563        5.63       79.01
         20 |        529        5.29       84.30
         21 |        515        5.15       89.45
         22 |        489        4.89       94.34
         23 |        449        4.49       98.83
         24 |          9        0.09       98.92
         99 |        108        1.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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