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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,947       99.47       99.47
          1 |         12        0.12       99.59
          2 |          4        0.04       99.63
          3 |          6        0.06       99.69
          9 |         31        0.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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