Frequencies for first 10,000 rows of rechal variable in drug2014q3 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      1,578       15.78       15.78
          D |      6,141       61.41       77.19
          N |        169        1.69       78.88
          U |      2,089       20.89       99.77
          Y |         23        0.23      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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