Frequencies for first 10,000 rows of dlmp_yy variable in natl2015 dataset :

Last Normal |
Menses Year |
  nnnn Year |
    of last |
     normal |
     menses |      Freq.     Percent        Cum.
------------+-----------------------------------
       2014 |      7,922       79.22       79.22
       2015 |      1,352       13.52       92.74
       9999 |        726        7.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Oct 2016