Frequencies for first 10,000 rows of mpre10 variable in natl1980 dataset :

      Month |
   Prenatal |
 Care began |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,745       47.45       47.45
          2 |      2,182       21.82       69.27
          3 |      1,100       11.00       80.27
          4 |        677        6.77       87.04
          5 |        455        4.55       91.59
          6 |        336        3.36       94.95
          7 |        199        1.99       96.94
          8 |         98        0.98       97.92
          9 |        125        1.25       99.17
         10 |         83        0.83      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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