Frequencies for first 10,000 rows of dmage variable in natlterr1998 dataset :

     Age of |
     Mother |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |          1        0.01        0.01
         13 |         11        0.11        0.12
         14 |         46        0.46        0.58
         15 |        155        1.55        2.13
         16 |        272        2.72        4.85
         17 |        416        4.16        9.01
         18 |        549        5.49       14.50
         19 |        603        6.03       20.53
         20 |        644        6.44       26.97
         21 |        700        7.00       33.97
         22 |        626        6.26       40.23
         23 |        631        6.31       46.54
         24 |        577        5.77       52.31
         25 |        545        5.45       57.76
         26 |        554        5.54       63.30
         27 |        509        5.09       68.39
         28 |        442        4.42       72.81
         29 |        433        4.33       77.14
         30 |        421        4.21       81.35
         31 |        353        3.53       84.88
         32 |        300        3.00       87.88
         33 |        276        2.76       90.64
         34 |        226        2.26       92.90
         35 |        192        1.92       94.82
         36 |        127        1.27       96.09
         37 |        125        1.25       97.34
         38 |         91        0.91       98.25
         39 |         54        0.54       98.79
         40 |         44        0.44       99.23
         41 |         30        0.30       99.53
         42 |         16        0.16       99.69
         43 |         19        0.19       99.88
         44 |          6        0.06       99.94
         45 |          3        0.03       99.97
         46 |          1        0.01       99.98
         47 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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