Frequencies for first 10,000 rows of lmpmon variable in natl1977 dataset :

 Month Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         22        0.22        0.22
          2 |         89        0.89        1.11
          3 |      1,214       12.14       13.25
          4 |      3,733       37.33       50.58
          5 |      3,214       32.14       82.72
          6 |      1,181       11.81       94.53
          7 |        227        2.27       96.80
          8 |         51        0.51       97.31
          9 |         19        0.19       97.50
         10 |          4        0.04       97.54
         11 |          9        0.09       97.63
         12 |          8        0.08       97.71
         99 |        229        2.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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