Frequencies for first 10,000 rows of dlmp_yy variable in natl2003 dataset :

Last Normal |
   Menses - |
   Year U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
       2001 |          9        0.09        0.09
       2002 |      7,197       71.97       72.06
       2003 |      2,275       22.75       94.81
       9999 |        519        5.19      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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