Frequencies for impacts variable in person dataset :

    VEHICLE |
       ROLE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         24        2.23        2.23
          1 |        596       55.34       57.57
          2 |        249       23.12       80.69
          3 |         15        1.39       82.08
          . |        193       17.92      100.00
------------+-----------------------------------
      Total |      1,077      100.00

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