Frequencies for first 10,000 rows of dechal variable in drug2004q1 dataset :

Dechallenge |
      code, |
 indicating |
if reaction |
abated when |
       drug |
therapy was |
    stopped |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      7,919       79.19       79.19
          D |      1,284       12.84       92.03
          N |        152        1.52       93.55
          U |        222        2.22       95.77
          Y |        423        4.23      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Dec 2015