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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,231       92.31       92.31
          1 |        643        6.43       98.74
          2 |         43        0.43       99.17
          3 |          5        0.05       99.22
          9 |         78        0.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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