Frequencies for first 10,000 rows of birmon variable in natl1993 dataset :

   Month of |
      Birth |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,928       49.28       49.28
          2 |      4,183       41.83       91.11
          3 |        889        8.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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