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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,265       92.65       92.65
          1 |        566        5.66       98.31
          2 |         64        0.64       98.95
          3 |          3        0.03       98.98
          4 |          3        0.03       99.01
          9 |         99        0.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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