Frequencies for first 10,000 rows of dechal variable in drug2013q2 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,818       98.18       98.18
          D |        114        1.14       99.32
          N |         13        0.13       99.45
          U |         16        0.16       99.61
          Y |         39        0.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Apr 2017