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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        931        9.31        9.31
          1 |      6,340       63.40       72.71
          2 |      1,528       15.28       87.99
          3 |        372        3.72       91.71
          9 |          9        0.09       91.80
          . |        820        8.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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