Frequencies for impacts variable in person dataset :

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        159       12.03       12.03
          1 |        876       66.26       78.29
          2 |         14        1.06       79.35
          3 |         17        1.29       80.64
          . |        256       19.36      100.00
------------+-----------------------------------
      Total |      1,322      100.00

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