Frequencies for first 10,000 rows of dob_mm variable in natl2005 dataset :

Birth Month |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        797        7.97        7.97
          2 |        753        7.53       15.50
          3 |        960        9.60       25.10
          4 |        847        8.47       33.57
          5 |        852        8.52       42.09
          6 |        915        9.15       51.24
          7 |        864        8.64       59.88
          8 |        889        8.89       68.77
          9 |        868        8.68       77.45
         10 |        824        8.24       85.69
         11 |        848        8.48       94.17
         12 |        583        5.83      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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