Frequencies for first 10,000 rows of dechal variable in drug2014q1 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,840       98.40       98.40
          D |        103        1.03       99.43
          N |         10        0.10       99.53
          U |         34        0.34       99.87
          Y |         13        0.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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