Frequencies for first 10,000 rows of dfage variable in natl1992 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         15 |          2        0.02        0.02
         16 |          3        0.03        0.05
         17 |         16        0.16        0.21
         18 |         67        0.67        0.88
         19 |        130        1.30        2.18
         20 |        175        1.75        3.93
         21 |        254        2.54        6.47
         22 |        277        2.77        9.24
         23 |        292        2.92       12.16
         24 |        354        3.54       15.70
         25 |        388        3.88       19.58
         26 |        424        4.24       23.82
         27 |        432        4.32       28.14
         28 |        461        4.61       32.75
         29 |        414        4.14       36.89
         30 |        468        4.68       41.57
         31 |        403        4.03       45.60
         32 |        395        3.95       49.55
         33 |        323        3.23       52.78
         34 |        267        2.67       55.45
         35 |        220        2.20       57.65
         36 |        210        2.10       59.75
         37 |        157        1.57       61.32
         38 |        129        1.29       62.61
         39 |         98        0.98       63.59
         40 |         92        0.92       64.51
         41 |         68        0.68       65.19
         42 |         50        0.50       65.69
         43 |         40        0.40       66.09
         44 |         44        0.44       66.53
         45 |         22        0.22       66.75
         46 |         19        0.19       66.94
         47 |         11        0.11       67.05
         48 |         11        0.11       67.16
         49 |         11        0.11       67.27
         50 |          5        0.05       67.32
         51 |          4        0.04       67.36
         52 |          2        0.02       67.38
         53 |          3        0.03       67.41
         54 |          6        0.06       67.47
         55 |          4        0.04       67.51
         56 |          6        0.06       67.57
         57 |          2        0.02       67.59
         59 |          1        0.01       67.60
         60 |          1        0.01       67.61
         65 |          1        0.01       67.62
         68 |          1        0.01       67.63
         69 |          1        0.01       67.64
         99 |      3,236       32.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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