Frequencies for phaz_rel variable in parkwork dataset :

  Hazardous |
  Materials |
Involvement |
/Placard-HM |
 5 Released |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,061       99.72       99.72
          1 |          3        0.28      100.00
------------+-----------------------------------
      Total |      1,064      100.00

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