Frequencies for first 10,000 rows of lmpyr variable in natl1989 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
       1988 |      9,510       95.10       95.10
       1989 |         79        0.79       95.89
       9999 |        411        4.11      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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