Frequencies for first 10,000 rows of ewarno variable in nhamcsopd2007 dataset :

   if yes, are |
there warnings |
       of drug |
 interactions? |      Freq.     Percent        Cum.
---------------+-----------------------------------
not applicable |      6,080       60.80       60.80
           yes |      2,778       27.78       88.58
            no |      1,142       11.42      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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