Frequencies for first 10,000 rows of mpre6 variable in natl1986 dataset :

      Month |
   Prenatal |
 Care began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      5,072       50.72       50.72
          2 |      2,054       20.54       71.26
          3 |      2,043       20.43       91.69
          4 |        496        4.96       96.65
          5 |        214        2.14       98.79
          6 |        121        1.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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