Frequencies for first 10,000 rows of lmpmon variable in natl1978 dataset :

 Month Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         22        0.22        0.22
          2 |         86        0.86        1.08
          3 |      1,192       11.92       13.00
          4 |      3,664       36.64       49.64
          5 |      3,357       33.57       83.21
          6 |      1,205       12.05       95.26
          7 |        215        2.15       97.41
          8 |         46        0.46       97.87
          9 |         15        0.15       98.02
         10 |          7        0.07       98.09
         11 |          8        0.08       98.17
         12 |          4        0.04       98.21
         99 |        179        1.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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