Frequencies for first 10,000 rows of ewarne variable in nhamcsed2008 dataset :

   if yes, are |
there warnings |
       of drug |
 interactions? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |         70        0.70        0.70
       unknown |        321        3.21        3.91
not applicable |      4,196       41.96       45.87
           yes |      4,420       44.20       90.07
            no |        901        9.01       99.08
    turned off |         92        0.92      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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