Frequencies for first 10,000 rows of ewarn variable in namcs2008 dataset :

   if yes, are |
there warnings |
       of drug |
interact/contr |
         aind? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |        242        2.42        2.42
       unknown |        259        2.59        5.01
not applicable |      5,319       53.19       58.20
           yes |      3,623       36.23       94.43
            no |        547        5.47       99.90
    turned off |         10        0.10      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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