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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,850       98.50       98.50
          1 |         26        0.26       98.76
          2 |          3        0.03       98.79
          3 |          3        0.03       98.82
          9 |        118        1.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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