Frequencies for first 10,000 rows of mpre6 variable in natl1978 dataset :

      Month |
   Prenatal |
 Care began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,516       45.16       45.16
          2 |      2,402       24.02       69.18
          3 |      2,309       23.09       92.27
          4 |        573        5.73       98.00
          5 |        124        1.24       99.24
          6 |         76        0.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016