Frequencies for first 10,000 rows of dlmp_yy variable in natl2006 dataset :

Last Normal |
   Menses - |
   Year U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
       2004 |         12        0.12        0.12
       2005 |      7,986       79.86       79.98
       2006 |      1,696       16.96       96.94
       9999 |        306        3.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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