Frequencies for first 10,000 rows of dmage variable in natlterr1995 dataset :

     Age of |
     Mother |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |          1        0.01        0.01
         13 |         11        0.11        0.12
         14 |         59        0.59        0.71
         15 |        172        1.72        2.43
         16 |        284        2.84        5.27
         17 |        430        4.30        9.57
         18 |        516        5.16       14.73
         19 |        621        6.21       20.94
         20 |        627        6.27       27.21
         21 |        586        5.86       33.07
         22 |        668        6.68       39.75
         23 |        632        6.32       46.07
         24 |        611        6.11       52.18
         25 |        570        5.70       57.88
         26 |        515        5.15       63.03
         27 |        481        4.81       67.84
         28 |        508        5.08       72.92
         29 |        478        4.78       77.70
         30 |        396        3.96       81.66
         31 |        367        3.67       85.33
         32 |        323        3.23       88.56
         33 |        236        2.36       90.92
         34 |        215        2.15       93.07
         35 |        190        1.90       94.97
         36 |        129        1.29       96.26
         37 |        102        1.02       97.28
         38 |         99        0.99       98.27
         39 |         74        0.74       99.01
         40 |         33        0.33       99.34
         41 |         27        0.27       99.61
         42 |         19        0.19       99.80
         43 |         10        0.10       99.90
         44 |          1        0.01       99.91
         45 |          1        0.01       99.92
         46 |          3        0.03       99.95
         47 |          3        0.03       99.98
         49 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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