Frequencies for first 10,000 rows of lmpyr variable in natl1978 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          - |        218        2.18        2.18
          7 |      9,755       97.55       99.73
          8 |         27        0.27      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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