Frequencies for first 10,000 rows of monpre variable in natl1995 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         93        0.93        0.93
          1 |      1,778       17.78       18.71
          2 |      4,499       44.99       63.70
          3 |      1,863       18.63       82.33
          4 |        767        7.67       90.00
          5 |        429        4.29       94.29
          6 |        260        2.60       96.89
          7 |        142        1.42       98.31
          8 |         80        0.80       99.11
          9 |         12        0.12       99.23
         99 |         77        0.77      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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