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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,825       98.25       98.25
          1 |         21        0.21       98.46
          2 |          2        0.02       98.48
          3 |          2        0.02       98.50
          9 |        150        1.50      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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