Frequencies for first 10,000 rows of dlmp_yy variable in natl2013 dataset :

Last Normal |
   Menses - |
   Year U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
       2012 |      7,871       78.71       78.71
       2013 |      1,312       13.12       91.83
       9999 |        817        8.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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