Frequencies for first 10,000 rows of toxscren variable in nhamcsed2009 dataset :

 toxicology |
     screen |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,665       96.65       96.65
          1 |        335        3.35      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016