Frequencies for first 10,000 rows of mpre6 variable in natl1998 dataset :

      Month |
   Prenatal |
 Care Began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      6,408       64.08       64.08
          2 |      1,751       17.51       81.59
          3 |      1,378       13.78       95.37
          4 |        306        3.06       98.43
          5 |        131        1.31       99.74
          6 |         26        0.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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