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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,680       86.80       86.80
          1 |        497        4.97       91.77
          2 |         38        0.38       92.15
          4 |          4        0.04       92.19
          9 |         56        0.56       92.75
          . |        725        7.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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