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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,883       98.83       98.83
          1 |         17        0.17       99.00
          2 |          2        0.02       99.02
          3 |          9        0.09       99.11
          9 |         89        0.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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