Frequencies for first 10,000 rows of monpre variable in natlterr1999 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         85        0.85        0.85
          1 |      1,411       14.11       14.96
          2 |      4,016       40.16       55.12
          3 |      2,252       22.52       77.64
          4 |      1,056       10.56       88.20
          5 |        553        5.53       93.73
          6 |        313        3.13       96.86
          7 |        156        1.56       98.42
          8 |         94        0.94       99.36
          9 |         21        0.21       99.57
         99 |         43        0.43      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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