Frequencies for first 10,000 rows of mpre6 variable in natl1987 dataset :

      Month |
   Prenatal |
 Care began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      5,226       52.26       52.26
          2 |      1,967       19.67       71.93
          3 |      2,046       20.46       92.39
          4 |        452        4.52       96.91
          5 |        213        2.13       99.04
          6 |         96        0.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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