Frequencies for first 10,000 rows of rechal variable in drug2018q2 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,527       85.27       85.27
          N |         94        0.94       86.21
          U |      1,353       13.53       99.74
          Y |         26        0.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 8 Sep 2018