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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,283       92.83       92.83
          1 |        565        5.65       98.48
          2 |         58        0.58       99.06
          3 |          1        0.01       99.07
          4 |          3        0.03       99.10
          9 |         90        0.90      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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