Frequencies for first 10,000 rows of mage12 variable in natlterr1995 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         71        0.71        0.71
          3 |        172        1.72        2.43
          4 |        284        2.84        5.27
          5 |        430        4.30        9.57
          6 |        516        5.16       14.73
          7 |        621        6.21       20.94
          8 |      3,124       31.24       52.18
          9 |      2,552       25.52       77.70
         10 |      1,537       15.37       93.07
         11 |        594        5.94       99.01
         12 |         90        0.90       99.91
         13 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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