Frequencies for first 10,000 rows of mage12 variable in natlterr1994 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         75        0.75        0.75
          3 |        152        1.52        2.27
          4 |        322        3.22        5.49
          5 |        440        4.40        9.89
          6 |        520        5.20       15.09
          7 |        573        5.73       20.82
          8 |      3,176       31.76       52.58
          9 |      2,597       25.97       78.55
         10 |      1,439       14.39       92.94
         11 |        600        6.00       98.94
         12 |        104        1.04       99.98
         13 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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