Frequencies for first 10,000 rows of dfage variable in natlterr1996 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         13 |          1        0.01        0.01
         14 |          4        0.04        0.05
         15 |         15        0.15        0.20
         16 |         65        0.65        0.85
         17 |        137        1.37        2.22
         18 |        278        2.78        5.00
         19 |        392        3.92        8.92
         20 |        479        4.79       13.71
         21 |        564        5.64       19.35
         22 |        568        5.68       25.03
         23 |        584        5.84       30.87
         24 |        614        6.14       37.01
         25 |        630        6.30       43.31
         26 |        582        5.82       49.13
         27 |        539        5.39       54.52
         28 |        480        4.80       59.32
         29 |        481        4.81       64.13
         30 |        467        4.67       68.80
         31 |        419        4.19       72.99
         32 |        327        3.27       76.26
         33 |        328        3.28       79.54
         34 |        252        2.52       82.06
         35 |        251        2.51       84.57
         36 |        181        1.81       86.38
         37 |        181        1.81       88.19
         38 |        156        1.56       89.75
         39 |        132        1.32       91.07
         40 |        111        1.11       92.18
         41 |         96        0.96       93.14
         42 |         65        0.65       93.79
         43 |         69        0.69       94.48
         44 |         57        0.57       95.05
         45 |         46        0.46       95.51
         46 |         44        0.44       95.95
         47 |         31        0.31       96.26
         48 |         34        0.34       96.60
         49 |         27        0.27       96.87
         50 |         19        0.19       97.06
         51 |         16        0.16       97.22
         52 |         11        0.11       97.33
         53 |         14        0.14       97.47
         54 |         10        0.10       97.57
         55 |          7        0.07       97.64
         56 |          8        0.08       97.72
         57 |          7        0.07       97.79
         58 |          6        0.06       97.85
         59 |          3        0.03       97.88
         61 |          5        0.05       97.93
         62 |          3        0.03       97.96
         65 |          1        0.01       97.97
         66 |          1        0.01       97.98
         67 |          2        0.02       98.00
         71 |          2        0.02       98.02
         74 |          1        0.01       98.03
         99 |        197        1.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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