Frequencies for veh_no variable in vision dataset :

    Vehicle |
     Number |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        330       73.50       73.50
          2 |        100       22.27       95.77
          3 |         15        3.34       99.11
          4 |          4        0.89      100.00
------------+-----------------------------------
      Total |        449      100.00

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