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

  HAZARDOUS |
MATERIAL-ID |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,973       99.73       99.73
       1075 |          2        0.02       99.75
       1203 |          7        0.07       99.82
       1208 |          1        0.01       99.83
       1247 |          1        0.01       99.84
       1267 |          1        0.01       99.85
       1866 |          1        0.01       99.86
       1993 |          1        0.01       99.87
       2032 |          1        0.01       99.88
       2211 |          1        0.01       99.89
       3077 |          2        0.02       99.91
       3082 |          1        0.01       99.92
       3257 |          1        0.01       99.93
       8888 |          7        0.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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