Frequencies for first 10,000 rows of birmon variable in natlterr1999 dataset :

   Month of |
      Birth |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,862       48.62       48.62
          2 |      4,159       41.59       90.21
          3 |        979        9.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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