Frequencies for first 10,000 rows of monpre variable in natlterr1998 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        105        1.05        1.05
          1 |      1,440       14.40       15.45
          2 |      4,038       40.38       55.83
          3 |      2,293       22.93       78.76
          4 |      1,146       11.46       90.22
          5 |        539        5.39       95.61
          6 |        242        2.42       98.03
          7 |        121        1.21       99.24
          8 |         38        0.38       99.62
          9 |         13        0.13       99.75
         99 |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015