Frequencies for first 10,000 rows of mpre6 variable in natl1991 dataset :

      Month |
   Prenatal |
 Care Began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      5,393       53.93       53.93
          2 |      2,003       20.03       73.96
          3 |      1,987       19.87       93.83
          4 |        412        4.12       97.95
          5 |        158        1.58       99.53
          6 |         47        0.47      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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