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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,813       98.13       98.13
          1 |         22        0.22       98.35
          2 |          3        0.03       98.38
          3 |          5        0.05       98.43
          9 |        157        1.57      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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