Frequencies for first 10,000 rows of outcome variable in natl1976 dataset :

 Outcome of |
       Last |
  Pregnancy |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,074       40.74       40.74
          1 |      4,956       49.56       90.30
          2 |        742        7.42       97.72
          3 |        228        2.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016