Frequencies for first 10,000 rows of dlmp_yy variable in natlterr2009 dataset :

Last Normal |
   Menses - |
   Year U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
       2007 |          1        0.01        0.01
       2008 |      6,459       64.59       64.60
       2009 |      2,169       21.69       86.29
       9999 |      1,371       13.71      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015