Frequencies for first 10,000 rows of rechal variable in drug2014q4 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |        257        2.57        2.57
          D |      8,319       83.19       85.76
          N |        134        1.34       87.10
          U |      1,272       12.72       99.82
          Y |         18        0.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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