Frequencies for first 10,000 rows of mpre6 variable in natl1999 dataset :

      Month |
   Prenatal |
 Care Began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      6,631       66.31       66.31
          2 |      1,652       16.52       82.83
          3 |      1,313       13.13       95.96
          4 |        249        2.49       98.45
          5 |        138        1.38       99.83
          6 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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