Frequencies for first 10,000 rows of birmon variable in natl1998 dataset :

   Month of |
      Birth |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      5,104       51.04       51.04
          2 |      4,591       45.91       96.95
          3 |        305        3.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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