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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,290       92.90       92.90
          1 |        545        5.45       98.35
          2 |         63        0.63       98.98
          4 |          2        0.02       99.00
          9 |        100        1.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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