Frequencies for first 10,000 rows of mage12 variable in natlterr1996 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         60        0.60        0.60
          3 |        145        1.45        2.05
          4 |        311        3.11        5.16
          5 |        450        4.50        9.66
          6 |        507        5.07       14.73
          7 |        620        6.20       20.93
          8 |      3,143       31.43       52.36
          9 |      2,552       25.52       77.88
         10 |      1,463       14.63       92.51
         11 |        637        6.37       98.88
         12 |        106        1.06       99.94
         13 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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