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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,269       92.69       92.69
          1 |        553        5.53       98.22
          2 |         71        0.71       98.93
          9 |        107        1.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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