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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        934        9.34        9.34
          1 |      6,060       60.60       69.94
          2 |      1,960       19.60       89.54
          3 |        172        1.72       91.26
          9 |         12        0.12       91.38
          . |        862        8.62      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016