Frequencies for haz_carg variable in vehnit dataset :

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,381       99.14       99.14
          2 |          1        0.07       99.21
          9 |         11        0.79      100.00
------------+-----------------------------------
      Total |      1,393      100.00

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