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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,815       18.15       18.15
          1 |      5,847       58.47       76.62
          2 |      2,137       21.37       97.99
          3 |        175        1.75       99.74
          9 |         26        0.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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