Frequencies for first 10,000 rows of haz_carg variable in vehicle dataset :

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,860       98.60       98.60
          1 |         27        0.27       98.87
          2 |          3        0.03       98.90
          3 |          2        0.02       98.92
          9 |        108        1.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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