Frequencies for first 10,000 rows of dob_mm variable in natl2003 dataset :

Birth Month |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        830        8.30        8.30
          2 |        752        7.52       15.82
          3 |        869        8.69       24.51
          4 |        826        8.26       32.77
          5 |        814        8.14       40.91
          6 |        828        8.28       49.19
          7 |        884        8.84       58.03
          8 |        892        8.92       66.95
          9 |        893        8.93       75.88
         10 |        812        8.12       84.00
         11 |        778        7.78       91.78
         12 |        822        8.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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