Frequencies for first 10,000 rows of mpre10 variable in natl1977 dataset :

      Month |
   Prenatal |
 Care began |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,445       44.45       44.45
          2 |      2,384       23.84       68.29
          3 |      1,256       12.56       80.85
          4 |        727        7.27       88.12
          5 |        458        4.58       92.70
          6 |        287        2.87       95.57
          7 |        164        1.64       97.21
          8 |         90        0.90       98.11
          9 |        124        1.24       99.35
         10 |         65        0.65      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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