Frequencies for first 10,000 rows of dechal variable in drug2017q2 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      5,209       52.09       52.09
          D |      1,545       15.45       67.54
          N |        114        1.14       68.68
          U |      2,165       21.65       90.33
          Y |        967        9.67      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 8 Feb 2018