Frequencies for first 10,000 rows of dechal variable in drug2013q3 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,774       97.74       97.74
          D |        137        1.37       99.11
          N |         20        0.20       99.31
          U |         35        0.35       99.66
          Y |         34        0.34      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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