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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,698       86.98       86.98
          1 |        501        5.01       91.99
          2 |         12        0.12       92.11
          3 |          1        0.01       92.12
          9 |         95        0.95       93.07
          . |        693        6.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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