Frequencies for first 10,000 rows of ewarne variable in nhamcsed2006 dataset :

   if yes, are |
there warnings |
       of drug |
 interactions? |      Freq.     Percent        Cum.
---------------+-----------------------------------
           yes |      2,053       20.53       20.53
            no |        529        5.29       25.82
       unknown |        246        2.46       28.28
not applicable |      6,662       66.62       94.90
         blank |        510        5.10      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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