Frequencies for first 10,000 rows of dfage variable in natl1999 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         15 |          4        0.04        0.04
         16 |          6        0.06        0.10
         17 |         50        0.50        0.60
         18 |        113        1.13        1.73
         19 |        186        1.86        3.59
         20 |        254        2.54        6.13
         21 |        276        2.76        8.89
         22 |        364        3.64       12.53
         23 |        350        3.50       16.03
         24 |        391        3.91       19.94
         25 |        411        4.11       24.05
         26 |        448        4.48       28.53
         27 |        447        4.47       33.00
         28 |        544        5.44       38.44
         29 |        509        5.09       43.53
         30 |        420        4.20       47.73
         31 |        417        4.17       51.90
         32 |        359        3.59       55.49
         33 |        319        3.19       58.68
         34 |        311        3.11       61.79
         35 |        284        2.84       64.63
         36 |        237        2.37       67.00
         37 |        192        1.92       68.92
         38 |        147        1.47       70.39
         39 |        124        1.24       71.63
         40 |        102        1.02       72.65
         41 |         79        0.79       73.44
         42 |         71        0.71       74.15
         43 |         58        0.58       74.73
         44 |         48        0.48       75.21
         45 |         35        0.35       75.56
         46 |         27        0.27       75.83
         47 |         26        0.26       76.09
         48 |         14        0.14       76.23
         49 |         17        0.17       76.40
         50 |         18        0.18       76.58
         51 |          7        0.07       76.65
         52 |          6        0.06       76.71
         53 |          3        0.03       76.74
         54 |          5        0.05       76.79
         55 |          3        0.03       76.82
         56 |          1        0.01       76.83
         58 |          1        0.01       76.84
         59 |          3        0.03       76.87
         61 |          3        0.03       76.90
         62 |          1        0.01       76.91
         77 |          1        0.01       76.92
         79 |          1        0.01       76.93
         99 |      2,307       23.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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