Frequencies for first 10,000 rows of mage15 variable in natl1970 dataset :

     Age of |
     Mother |
  recode 15 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         57        0.57        0.57
          3 |        150        1.50        2.07
          4 |        303        3.03        5.10
          5 |        457        4.57        9.67
          6 |        657        6.57       16.24
          7 |        779        7.79       24.03
          9 |        831        8.31       32.34
         10 |        841        8.41       40.75
         11 |        815        8.15       48.90
         12 |        757        7.57       56.47
         13 |        546        5.46       61.93
         14 |      2,200       22.00       83.93
         15 |        980        9.80       93.73
         16 |        479        4.79       98.52
         17 |        148        1.48      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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