Frequencies for first 10,000 rows of rechal variable in drug2013q1 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |        909        9.09        9.09
          D |      7,495       74.95       84.04
          N |        198        1.98       86.02
          U |      1,377       13.77       99.79
          Y |         21        0.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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