Frequencies for first 10,000 rows of dechal variable in drug2004q2 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,164       81.64       81.64
          D |      1,076       10.76       92.40
          N |        149        1.49       93.89
          U |        240        2.40       96.29
          Y |        371        3.71      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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