Frequencies for first 10,000 rows of monpre variable in natlterr1996 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        104        1.04        1.04
          1 |      1,157       11.57       12.61
          2 |      4,245       42.45       55.06
          3 |      2,297       22.97       78.03
          4 |      1,113       11.13       89.16
          5 |        591        5.91       95.07
          6 |        270        2.70       97.77
          7 |        130        1.30       99.07
          8 |         59        0.59       99.66
          9 |         14        0.14       99.80
         99 |         20        0.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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