Frequencies for first 10,000 rows of retappt variable in namcs2000 dataset :

  return at |
  specified |
       time |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,634       46.34       46.34
          1 |      5,366       53.66      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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