Frequencies for first 10,000 rows of retprn variable in nhamcsed2002 dataset :

  return if |
    needed, |
p.r.n./appt |
          . |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,371       63.71       63.71
          1 |      3,629       36.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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