Frequencies for first 10,000 rows of mage12 variable in natl1986 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         51        0.51        0.51
          3 |        126        1.26        1.77
          4 |        226        2.26        4.03
          5 |        364        3.64        7.67
          6 |        520        5.20       12.87
          7 |        599        5.99       18.86
          8 |      3,290       32.90       51.76
          9 |      2,820       28.20       79.96
         10 |      1,502       15.02       94.98
         11 |        443        4.43       99.41
         12 |         56        0.56       99.97
         13 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016