Frequencies for first 10,000 rows of dob_mm variable in natl2013 dataset :

Birth Month |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        968        9.68        9.68
          2 |        832        8.32       18.00
          3 |        966        9.66       27.66
          4 |        911        9.11       36.77
          5 |        937        9.37       46.14
          6 |        978        9.78       55.92
          7 |        951        9.51       65.43
          8 |      1,026       10.26       75.69
          9 |        944        9.44       85.13
         10 |        946        9.46       94.59
         11 |        541        5.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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