Frequencies for first 10,000 rows of lmpyr variable in natl1992 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
       1991 |      9,740       97.40       97.40
       1992 |          1        0.01       97.41
       9999 |        259        2.59      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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