Frequencies for first 10,000 rows of lmpyr variable in natl1977 dataset :

  Year Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          - |        161        1.61        1.61
          6 |      9,817       98.17       99.78
          7 |         22        0.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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