Frequencies for first 10,000 rows of toxscren variable in nhamcsed2015 dataset 

 Toxicology |
     screen |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,552       95.52       95.52
        Yes |        448        4.48      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Nov 2017