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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,845       98.45       98.45
          1 |         21        0.21       98.66
          2 |          3        0.03       98.69
          3 |          3        0.03       98.72
          9 |        128        1.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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