Frequencies for first 10,000 rows of dechal variable in drug2008q2 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,694       86.94       86.94
          D |        677        6.77       93.71
          N |         74        0.74       94.45
          U |        185        1.85       96.30
          Y |        370        3.70      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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