Frequencies for first 10,000 rows of lmpyr variable in natl1987 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          - |        253        2.53        2.53
          6 |      9,681       96.81       99.34
          7 |         66        0.66      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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