Frequencies for first 10,000 rows of lmpmon variable in natl1987 dataset :

 Month Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         30        0.30        0.30
          2 |        117        1.17        1.47
          3 |      1,141       11.41       12.88
          4 |      3,554       35.54       48.42
          5 |      3,308       33.08       81.50
          6 |      1,271       12.71       94.21
          7 |        238        2.38       96.59
          8 |         73        0.73       97.32
          9 |         16        0.16       97.48
         10 |          4        0.04       97.52
         11 |         12        0.12       97.64
         12 |         11        0.11       97.75
         99 |        225        2.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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