Frequencies for first 10,000 rows of lmpyr variable in natlterr1994 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
       1993 |      9,787       97.87       97.87
       9999 |        213        2.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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