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

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,250       82.50       82.50
          N |        227        2.27       84.77
          U |      1,502       15.02       99.79
          Y |         21        0.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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