Frequencies for first 10,000 rows of toxscren variable in nhamcsed2007 dataset :

 toxicology |
     screen |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,571       95.71       95.71
        yes |        429        4.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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