Frequencies for first 10,000 rows of mpcb variable in natlterr2003 dataset :

      Month |
   Prenatal |
 Care Began |
          U |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         71        0.71        0.71
          1 |      1,654       16.54       17.25
          2 |      4,187       41.87       59.12
          3 |      2,309       23.09       82.21
          4 |        876        8.76       90.97
          5 |        440        4.40       95.37
          6 |        226        2.26       97.63
          7 |        108        1.08       98.71
          8 |         81        0.81       99.52
          9 |         31        0.31       99.83
         99 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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