Frequencies for first 10,000 rows of monpre variable in natlterr2002 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         71        0.71        0.71
          1 |      1,656       16.56       17.27
          2 |      4,115       41.15       58.42
          3 |      2,241       22.41       80.83
          4 |        896        8.96       89.79
          5 |        474        4.74       94.53
          6 |        264        2.64       97.17
          7 |        154        1.54       98.71
          8 |         90        0.90       99.61
          9 |         22        0.22       99.83
         99 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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