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

    Vehicle |
       Role |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        846        8.46        8.46
          1 |      6,772       67.72       76.18
          2 |      2,119       21.19       97.37
          3 |        235        2.35       99.72
          9 |         28        0.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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