Frequencies for first 10,000 rows of mage12 variable in natl2002 dataset :

     Age of |
     Mother |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         16        0.16        0.16
          3 |         38        0.38        0.54
          4 |        100        1.00        1.54
          5 |        189        1.89        3.43
          6 |        302        3.02        6.45
          7 |        465        4.65       11.10
          8 |      2,854       28.54       39.64
          9 |      2,630       26.30       65.94
         10 |      2,064       20.64       86.58
         11 |      1,042       10.42       97.00
         12 |        290        2.90       99.90
         13 |         10        0.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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