Frequencies for first 10,000 rows of dlmp_yy variable in natl2007 dataset :

Last Normal |
   Menses - |
   Year U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
       2006 |      7,888       78.88       78.88
       2007 |      1,679       16.79       95.67
       9999 |        433        4.33      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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