Frequencies for veh_no variable in per_aux dataset :

  VEHICLE # |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        239       16.08       16.08
          1 |        835       56.19       72.27
          2 |        343       23.08       95.36
          3 |         52        3.50       98.86
          4 |         13        0.87       99.73
          5 |          4        0.27      100.00
------------+-----------------------------------
      Total |      1,486      100.00

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