Frequencies for first 10,000 rows of lmpmon variable in natl1985 dataset :

 Month Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         19        0.19        0.19
          2 |        112        1.12        1.31
          3 |      1,114       11.14       12.45
          4 |      3,575       35.75       48.20
          5 |      3,275       32.75       80.95
          6 |      1,355       13.55       94.50
          7 |        257        2.57       97.07
          8 |         70        0.70       97.77
          9 |         19        0.19       97.96
         10 |         11        0.11       98.07
         11 |          8        0.08       98.15
         12 |         10        0.10       98.25
         99 |        175        1.75      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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