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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        909        9.09        9.09
          1 |      6,325       63.25       72.34
          2 |      1,651       16.51       88.85
          3 |        275        2.75       91.60
          9 |         19        0.19       91.79
          . |        821        8.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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