Frequencies for first 10,000 rows of monpre variable in natl1994 dataset :

     Detail |
   Month of |
  Pregnancy |
   Prenatal |
 Care Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        110        1.10        1.10
          1 |      1,638       16.38       17.48
          2 |      4,582       45.82       63.30
          3 |      1,918       19.18       82.48
          4 |        742        7.42       89.90
          5 |        425        4.25       94.15
          6 |        276        2.76       96.91
          7 |        141        1.41       98.32
          8 |         87        0.87       99.19
          9 |         39        0.39       99.58
         99 |         42        0.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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