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

  Hazardous |
  Materials |
Involvement |
/Placard-HM |
          1 |
-Involvemen |
          t |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      9,974       99.74       99.74
          2 |         26        0.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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