Frequencies for first 10,000 rows of mpre10 variable in natl1981 dataset :

      Month |
   Prenatal |
 Care began |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,787       47.87       47.87
          2 |      2,315       23.15       71.02
          3 |      1,131       11.31       82.33
          4 |        672        6.72       89.05
          5 |        439        4.39       93.44
          6 |        229        2.29       95.73
          7 |        148        1.48       97.21
          8 |         64        0.64       97.85
          9 |        142        1.42       99.27
         10 |         73        0.73      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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