Frequencies for first 10,000 rows of retappt variable in nhamcsopd1994 dataset :

  return at |
  specified |
       time |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,931       29.31       29.31
          1 |      7,069       70.69      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016