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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,223       92.23       92.23
          1 |        600        6.00       98.23
          2 |         58        0.58       98.81
          4 |          1        0.01       98.82
          9 |        118        1.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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