Frequencies for bus_use variable in vehicle dataset :

    BUS USE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        611       97.60       97.60
          4 |          1        0.16       97.76
          9 |         14        2.24      100.00
------------+-----------------------------------
      Total |        626      100.00

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