Frequencies for first 10,000 rows of rechal variable in drug2013q4 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |        744        7.44        7.44
          D |      8,067       80.67       88.11
          N |        290        2.90       91.01
          U |        886        8.86       99.87
          Y |         13        0.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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