Frequencies for first 10,000 rows of dechal variable in drug2006q3 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,447       94.47       94.47
          D |        253        2.53       97.00
          N |         46        0.46       97.46
          U |        115        1.15       98.61
          Y |        139        1.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Dec 2015