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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,711       87.11       87.11
          1 |        428        4.28       91.39
          2 |         23        0.23       91.62
          4 |          4        0.04       91.66
          9 |        107        1.07       92.73
          . |        727        7.27      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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