Frequencies for first 10,000 rows of mpre6 variable in natl1983 dataset :

      Month |
   Prenatal |
 Care began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,831       48.31       48.31
          2 |      2,211       22.11       70.42
          3 |      2,214       22.14       92.56
          4 |        510        5.10       97.66
          5 |        180        1.80       99.46
          6 |         54        0.54      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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