Frequencies for first 10,000 rows of dob_mm variable in natl2007 dataset :

Birth Month |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        856        8.56        8.56
          2 |        809        8.09       16.65
          3 |        897        8.97       25.62
          4 |        887        8.87       34.49
          5 |        940        9.40       43.89
          6 |        945        9.45       53.34
          7 |        907        9.07       62.41
          8 |        986        9.86       72.27
          9 |        970        9.70       81.97
         10 |        974        9.74       91.71
         11 |        791        7.91       99.62
         12 |         38        0.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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