Frequencies for haz_carg variable in vehicle dataset :

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        676       94.41       94.41
          1 |          1        0.14       94.55
          9 |         39        5.45      100.00
------------+-----------------------------------
      Total |        716      100.00

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