Frequencies for first 10,000 rows of dechal variable in drug2013q1 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,706       97.06       97.06
          D |        127        1.27       98.33
          N |         10        0.10       98.43
          U |         92        0.92       99.35
          Y |         65        0.65      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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