Frequencies for first 10,000 rows of monpre variable in natlterr1995 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        164        1.64        1.64
          1 |      1,177       11.77       13.41
          2 |      4,049       40.49       53.90
          3 |      2,336       23.36       77.26
          4 |      1,178       11.78       89.04
          5 |        529        5.29       94.33
          6 |        290        2.90       97.23
          7 |        148        1.48       98.71
          8 |         84        0.84       99.55
          9 |         20        0.20       99.75
         99 |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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