Frequencies for first 10,000 rows of ewarno variable in nhamcsopd2009 dataset :

   if yes, are |
there warnings |
       of drug |
 interactions? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |        168        1.68        1.68
       unknown |        387        3.87        5.55
not applicable |      5,571       55.71       61.26
           yes |      3,489       34.89       96.15
            no |        385        3.85      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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