Frequencies for first 10,000 rows of birmon variable in natl1991 dataset :

   Month of |
      Birth |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,640       46.40       46.40
          2 |      3,626       36.26       82.66
          3 |      1,734       17.34      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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