Frequencies for first 10,000 rows of dob_mm variable in natl2009 dataset :

Birth Month |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        677        6.77        6.77
          2 |        619        6.19       12.96
          3 |        673        6.73       19.69
          4 |        857        8.57       28.26
          5 |        922        9.22       37.48
          6 |        930        9.30       46.78
          7 |      1,168       11.68       58.46
          8 |      1,041       10.41       68.87
          9 |      1,100       11.00       79.87
         10 |      1,027       10.27       90.14
         11 |        545        5.45       95.59
         12 |        441        4.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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