Frequencies for first 10,000 rows of mage12 variable in natl1994 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         71        0.71        0.71
          3 |        127        1.27        1.98
          4 |        231        2.31        4.29
          5 |        381        3.81        8.10
          6 |        443        4.43       12.53
          7 |        615        6.15       18.68
          8 |      3,097       30.97       49.65
          9 |      2,606       26.06       75.71
         10 |      1,683       16.83       92.54
         11 |        657        6.57       99.11
         12 |         88        0.88       99.99
         13 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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