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

  HAZARDOUS |
      CARGO |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,937       99.37       99.37
          1 |         17        0.17       99.54
          2 |          3        0.03       99.57
          3 |          7        0.07       99.64
          9 |         36        0.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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