Frequencies for first 10,000 rows of mpre10 variable in natl1976 dataset :

      Month |
   Prenatal |
 Care began |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,446       44.46       44.46
          2 |      2,411       24.11       68.57
          3 |      1,237       12.37       80.94
          4 |        718        7.18       88.12
          5 |        431        4.31       92.43
          6 |        283        2.83       95.26
          7 |        193        1.93       97.19
          8 |         63        0.63       97.82
          9 |        122        1.22       99.04
         10 |         96        0.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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