Frequencies for first 10,000 rows of dechal variable in drug2017q4 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      4,715       47.15       47.15
          D |      1,603       16.03       63.18
          N |        163        1.63       64.81
          U |      2,346       23.46       88.27
          Y |      1,173       11.73      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Jun 2018