Frequencies for first 10,000 rows of precare variable in natl2013 dataset :

      Month |
   Prenatal |
 Care Began |
        RFP |
 668=f_mpcb |
          R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        106        1.06        1.06
          1 |        236        2.36        3.42
          2 |      2,529       25.29       28.71
          3 |      3,998       39.98       68.69
          4 |      1,148       11.48       80.17
          5 |        607        6.07       86.24
          6 |        376        3.76       90.00
          7 |        238        2.38       92.38
          8 |        175        1.75       94.13
          9 |        117        1.17       95.30
         10 |         13        0.13       95.43
         99 |        457        4.57      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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