Frequencies for first 10,000 rows of lmpyr variable in natl1988 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          - |        285        2.85        2.85
          7 |      9,711       97.11       99.96
          8 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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