Frequencies for first 10,000 rows of dfage variable in natl1994 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         15 |          1        0.01        0.01
         16 |          5        0.05        0.06
         17 |         19        0.19        0.25
         18 |         54        0.54        0.79
         19 |        112        1.12        1.91
         20 |        150        1.50        3.41
         21 |        209        2.09        5.50
         22 |        248        2.48        7.98
         23 |        311        3.11       11.09
         24 |        287        2.87       13.96
         25 |        324        3.24       17.20
         26 |        378        3.78       20.98
         27 |        403        4.03       25.01
         28 |        393        3.93       28.94
         29 |        443        4.43       33.37
         30 |        407        4.07       37.44
         31 |        387        3.87       41.31
         32 |        342        3.42       44.73
         33 |        332        3.32       48.05
         34 |        264        2.64       50.69
         35 |        188        1.88       52.57
         36 |        225        2.25       54.82
         37 |        175        1.75       56.57
         38 |        137        1.37       57.94
         39 |        115        1.15       59.09
         40 |         85        0.85       59.94
         41 |         71        0.71       60.65
         42 |         57        0.57       61.22
         43 |         42        0.42       61.64
         44 |         43        0.43       62.07
         45 |         25        0.25       62.32
         46 |         16        0.16       62.48
         47 |         15        0.15       62.63
         48 |         14        0.14       62.77
         49 |         10        0.10       62.87
         50 |         13        0.13       63.00
         51 |          7        0.07       63.07
         52 |          3        0.03       63.10
         53 |          1        0.01       63.11
         54 |          5        0.05       63.16
         57 |          2        0.02       63.18
         60 |          1        0.01       63.19
         61 |          1        0.01       63.20
         68 |          1        0.01       63.21
         99 |      3,679       36.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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