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

      TOWED |
   TRAILING |
       UNIT |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      8,778       87.78       87.78
          1 |        442        4.42       92.20
          2 |         34        0.34       92.54
          4 |          1        0.01       92.55
          9 |        114        1.14       93.69
          . |        631        6.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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