Frequencies for first 10,000 rows of mpre6 variable in natl1994 dataset :

      Month |
   Prenatal |
 Care Began |
   Recode 6 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      6,220       62.20       62.20
          2 |      1,918       19.18       81.38
          3 |      1,443       14.43       95.81
          4 |        267        2.67       98.48
          5 |        110        1.10       99.58
          6 |         42        0.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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