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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,768       87.68       87.68
          1 |        432        4.32       92.00
          2 |         40        0.40       92.40
          3 |          2        0.02       92.42
          9 |         15        0.15       92.57
          . |        743        7.43      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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