Frequencies for first 10,000 rows of rechal variable in drug2016q2 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,227       82.27       82.27
          N |        231        2.31       84.58
          U |      1,514       15.14       99.72
          Y |         28        0.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 6 Apr 2017