Frequencies for first 10,000 rows of dechal variable in drug2007q3 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,537       95.37       95.37
          D |        242        2.42       97.79
          N |         46        0.46       98.25
          U |         46        0.46       98.71
          Y |        129        1.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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