Frequencies for first 10,000 rows of dfage variable in natl1990 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         16 |          1        0.01        0.01
         17 |         26        0.26        0.27
         18 |         71        0.71        0.98
         19 |        160        1.60        2.58
         20 |        201        2.01        4.59
         21 |        270        2.70        7.29
         22 |        285        2.85       10.14
         23 |        323        3.23       13.37
         24 |        367        3.67       17.04
         25 |        460        4.60       21.64
         26 |        461        4.61       26.25
         27 |        515        5.15       31.40
         28 |        496        4.96       36.36
         29 |        437        4.37       40.73
         30 |        454        4.54       45.27
         31 |        400        4.00       49.27
         32 |        349        3.49       52.76
         33 |        326        3.26       56.02
         34 |        269        2.69       58.71
         35 |        244        2.44       61.15
         36 |        184        1.84       62.99
         37 |        144        1.44       64.43
         38 |        113        1.13       65.56
         39 |         92        0.92       66.48
         40 |         93        0.93       67.41
         41 |         63        0.63       68.04
         42 |         45        0.45       68.49
         43 |         33        0.33       68.82
         44 |         33        0.33       69.15
         45 |         14        0.14       69.29
         46 |         17        0.17       69.46
         47 |         11        0.11       69.57
         48 |         11        0.11       69.68
         49 |          8        0.08       69.76
         50 |          4        0.04       69.80
         51 |          2        0.02       69.82
         52 |          5        0.05       69.87
         53 |          3        0.03       69.90
         54 |          4        0.04       69.94
         55 |          1        0.01       69.95
         56 |          1        0.01       69.96
         57 |          3        0.03       69.99
         58 |          1        0.01       70.00
         59 |          1        0.01       70.01
         60 |          1        0.01       70.02
         62 |          1        0.01       70.03
         99 |      2,997       29.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016