Frequencies for first 10,000 rows of impacts variable in vehicle dataset :

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        404        4.04        4.04
          1 |      7,253       72.53       76.57
          2 |      1,982       19.82       96.39
          3 |        336        3.36       99.75
          9 |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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