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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,268       92.68       92.68
          1 |        545        5.45       98.13
          2 |         56        0.56       98.69
          4 |          1        0.01       98.70
          5 |          5        0.05       98.75
          9 |        125        1.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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