Frequencies for first 10,000 rows of dechal variable in drug2008q4 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,606       96.06       96.06
          D |        127        1.27       97.33
          N |         40        0.40       97.73
          U |         34        0.34       98.07
          Y |        193        1.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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