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

    VEHICLE |
       ROLE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        804        8.04        8.04
          1 |      5,376       53.76       61.80
          2 |      2,643       26.43       88.23
          3 |        415        4.15       92.38
          9 |        140        1.40       93.78
          . |        622        6.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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