Frequencies for first 10,000 rows of mage15 variable in natl1972 dataset :

     Age of |
     Mother |
  recode 15 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         74        0.74        0.74
          3 |        179        1.79        2.53
          4 |        321        3.21        5.74
          5 |        554        5.54       11.28
          6 |        672        6.72       18.00
          7 |        801        8.01       26.01
          9 |        784        7.84       33.85
         10 |        743        7.43       41.28
         11 |        728        7.28       48.56
         12 |        738        7.38       55.94
         13 |        746        7.46       63.40
         14 |      2,199       21.99       85.39
         15 |        922        9.22       94.61
         16 |        420        4.20       98.81
         17 |        119        1.19      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016