Frequencies for first 10,000 rows of mage12 variable in natl1993 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         77        0.77        0.77
          3 |        137        1.37        2.14
          4 |        279        2.79        4.93
          5 |        356        3.56        8.49
          6 |        509        5.09       13.58
          7 |        606        6.06       19.64
          8 |      3,120       31.20       50.84
          9 |      2,606       26.06       76.90
         10 |      1,653       16.53       93.43
         11 |        575        5.75       99.18
         12 |         80        0.80       99.98
         13 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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