Frequencies for first 10,000 rows of outcome variable in natl1977 dataset :

 Outcome of |
       Last |
  Pregnancy |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      3,928       39.28       39.28
          1 |      5,036       50.36       89.64
          2 |        743        7.43       97.07
          3 |        293        2.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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