Frequencies for first 10,000 rows of dmage variable in natlterr2001 dataset :

     Age of |
     Mother |      Freq.     Percent        Cum.
------------+-----------------------------------
         13 |          5        0.05        0.05
         14 |         41        0.41        0.46
         15 |        137        1.37        1.83
         16 |        262        2.62        4.45
         17 |        389        3.89        8.34
         18 |        544        5.44       13.78
         19 |        639        6.39       20.17
         20 |        686        6.86       27.03
         21 |        654        6.54       33.57
         22 |        677        6.77       40.34
         23 |        693        6.93       47.27
         24 |        559        5.59       52.86
         25 |        560        5.60       58.46
         26 |        484        4.84       63.30
         27 |        518        5.18       68.48
         28 |        437        4.37       72.85
         29 |        462        4.62       77.47
         30 |        396        3.96       81.43
         31 |        308        3.08       84.51
         32 |        297        2.97       87.48
         33 |        234        2.34       89.82
         34 |        244        2.44       92.26
         35 |        205        2.05       94.31
         36 |        161        1.61       95.92
         37 |        109        1.09       97.01
         38 |         82        0.82       97.83
         39 |         74        0.74       98.57
         40 |         62        0.62       99.19
         41 |         37        0.37       99.56
         42 |         22        0.22       99.78
         43 |          8        0.08       99.86
         44 |         12        0.12       99.98
         46 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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