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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        876        8.76        8.76
          1 |      6,406       64.06       72.82
          2 |      1,650       16.50       89.32
          3 |        254        2.54       91.86
          9 |         18        0.18       92.04
          . |        796        7.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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