Frequencies for first 10,000 rows of dechal variable in drug2015q1 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,929       99.29       99.29
          D |         53        0.53       99.82
          N |          5        0.05       99.87
          U |          5        0.05       99.92
          Y |          8        0.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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