Frequencies for first 10,000 rows of toxscren variable in nhamcsed2008 dataset :

 toxicology |
     screen |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,708       97.08       97.08
        yes |        292        2.92      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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