Frequencies for first 10,000 rows of rechal variable in drug2018q3 dataset :

Rechallenge |
      code, |
 indicating |
if reaction |
   recurred |
  when drug |
    therapy |
  restarted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,632       86.32       86.32
          N |         90        0.90       87.22
          U |      1,271       12.71       99.93
          Y |          7        0.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Mar 2019