Frequencies for first 10,000 rows of monpre variable in natl2002 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         44        0.44        0.44
          1 |      2,386       23.86       24.30
          2 |      3,280       32.80       57.10
          3 |      1,945       19.45       76.55
          4 |        750        7.50       84.05
          5 |        408        4.08       88.13
          6 |        266        2.66       90.79
          7 |        178        1.78       92.57
          8 |        117        1.17       93.74
          9 |        102        1.02       94.76
         99 |        524        5.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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