Frequencies for first 10,000 rows of birmon variable in natl1996 dataset :

   Month of |
      Birth |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,878       48.78       48.78
          2 |      4,334       43.34       92.12
          3 |        788        7.88      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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