Frequencies for first 10,000 rows of lmpyr variable in natl1997 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
       1996 |      9,697       96.97       96.97
       1997 |          3        0.03       97.00
       9999 |        300        3.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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