Frequencies for first 10,000 rows of ewarne variable in nhamcsed2009 dataset :

if yes, are |
      there |
warnings of |
       drug |
interaction |
         s? |      Freq.     Percent        Cum.
------------+-----------------------------------
         -8 |        793        7.93        7.93
         -7 |      3,163       31.63       39.56
          1 |      4,789       47.89       87.45
          2 |      1,255       12.55      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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