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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,870       98.70       98.70
          1 |         25        0.25       98.95
          2 |          1        0.01       98.96
          3 |          6        0.06       99.02
          9 |         98        0.98      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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