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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        968        9.68        9.68
          1 |      6,325       63.25       72.93
          2 |      1,573       15.73       88.66
          3 |        272        2.72       91.38
          9 |         10        0.10       91.48
          . |        852        8.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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