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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,178       91.78       91.78
          1 |        617        6.17       97.95
          2 |         76        0.76       98.71
          3 |          9        0.09       98.80
          4 |          5        0.05       98.85
          9 |        115        1.15      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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