Frequencies for first 10,000 rows of dmage variable in natlterr2002 dataset :

     Age of |
     Mother |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |          1        0.01        0.01
         13 |          7        0.07        0.08
         14 |         54        0.54        0.62
         15 |        106        1.06        1.68
         16 |        252        2.52        4.20
         17 |        386        3.86        8.06
         18 |        497        4.97       13.03
         19 |        592        5.92       18.95
         20 |        627        6.27       25.22
         21 |        673        6.73       31.95
         22 |        665        6.65       38.60
         23 |        674        6.74       45.34
         24 |        628        6.28       51.62
         25 |        580        5.80       57.42
         26 |        513        5.13       62.55
         27 |        498        4.98       67.53
         28 |        473        4.73       72.26
         29 |        417        4.17       76.43
         30 |        378        3.78       80.21
         31 |        338        3.38       83.59
         32 |        297        2.97       86.56
         33 |        267        2.67       89.23
         34 |        222        2.22       91.45
         35 |        208        2.08       93.53
         36 |        173        1.73       95.26
         37 |        115        1.15       96.41
         38 |        102        1.02       97.43
         39 |         87        0.87       98.30
         40 |         73        0.73       99.03
         41 |         44        0.44       99.47
         42 |         21        0.21       99.68
         43 |         20        0.20       99.88
         44 |          8        0.08       99.96
         45 |          3        0.03       99.99
         46 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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