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

    VEHICLE |
       ROLE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,168       11.68       11.68
          1 |      5,226       52.26       63.94
          2 |      2,449       24.49       88.43
          3 |        430        4.30       92.73
          9 |         96        0.96       93.69
          . |        631        6.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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