Frequencies for first 10,000 rows of dlmp_yy variable in natl2012 dataset :

Last Normal |
   Menses - |
   Year U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
       2011 |      7,857       78.57       78.57
       2012 |      1,597       15.97       94.54
       9999 |        546        5.46      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 5 May 2016