Frequencies for first 10,000 rows of dechal variable in drug2006q2 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,676       96.76       96.76
          D |        182        1.82       98.58
          N |         23        0.23       98.81
          U |         23        0.23       99.04
          Y |         96        0.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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