Frequencies for first 10,000 rows of dfage variable in natl2000 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         14 |          1        0.01        0.01
         15 |          5        0.05        0.06
         16 |         18        0.18        0.24
         17 |         62        0.62        0.86
         18 |         99        0.99        1.85
         19 |        199        1.99        3.84
         20 |        242        2.42        6.26
         21 |        328        3.28        9.54
         22 |        346        3.46       13.00
         23 |        333        3.33       16.33
         24 |        393        3.93       20.26
         25 |        382        3.82       24.08
         26 |        451        4.51       28.59
         27 |        438        4.38       32.97
         28 |        481        4.81       37.78
         29 |        457        4.57       42.35
         30 |        477        4.77       47.12
         31 |        417        4.17       51.29
         32 |        345        3.45       54.74
         33 |        358        3.58       58.32
         34 |        301        3.01       61.33
         35 |        270        2.70       64.03
         36 |        236        2.36       66.39
         37 |        198        1.98       68.37
         38 |        175        1.75       70.12
         39 |        132        1.32       71.44
         40 |        115        1.15       72.59
         41 |         86        0.86       73.45
         42 |         78        0.78       74.23
         43 |         74        0.74       74.97
         44 |         48        0.48       75.45
         45 |         29        0.29       75.74
         46 |         31        0.31       76.05
         47 |         27        0.27       76.32
         48 |         16        0.16       76.48
         49 |         19        0.19       76.67
         50 |         13        0.13       76.80
         51 |          7        0.07       76.87
         52 |          5        0.05       76.92
         53 |          8        0.08       77.00
         54 |          3        0.03       77.03
         55 |         11        0.11       77.14
         56 |          3        0.03       77.17
         57 |          2        0.02       77.19
         58 |          1        0.01       77.20
         59 |          1        0.01       77.21
         60 |          2        0.02       77.23
         62 |          1        0.01       77.24
         63 |          1        0.01       77.25
         64 |          1        0.01       77.26
         67 |          1        0.01       77.27
         99 |      2,273       22.73      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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