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

    VEHICLE |
       ROLE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        688        6.88        6.88
          1 |      6,937       69.37       76.25
          2 |      1,859       18.59       94.84
          3 |        458        4.58       99.42
          9 |         58        0.58      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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