Frequencies for first 10,000 rows of dechal variable in drug2016q4 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      5,354       53.54       53.54
          D |      1,445       14.45       67.99
          N |        155        1.55       69.54
          U |      2,109       21.09       90.63
          Y |        937        9.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Sep 2017