Frequencies for first 10,000 rows of lmpyr variable in natl1991 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
       1990 |      9,729       97.29       97.29
       9999 |        271        2.71      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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