Frequencies for first 10,000 rows of dfage variable in natl1993 dataset :

     Age of |
     Father |      Freq.     Percent        Cum.
------------+-----------------------------------
         16 |          2        0.02        0.02
         17 |         16        0.16        0.18
         18 |         62        0.62        0.80
         19 |        110        1.10        1.90
         20 |        172        1.72        3.62
         21 |        238        2.38        6.00
         22 |        290        2.90        8.90
         23 |        325        3.25       12.15
         24 |        323        3.23       15.38
         25 |        371        3.71       19.09
         26 |        376        3.76       22.85
         27 |        402        4.02       26.87
         28 |        472        4.72       31.59
         29 |        391        3.91       35.50
         30 |        410        4.10       39.60
         31 |        348        3.48       43.08
         32 |        310        3.10       46.18
         33 |        298        2.98       49.16
         34 |        247        2.47       51.63
         35 |        237        2.37       54.00
         36 |        199        1.99       55.99
         37 |        156        1.56       57.55
         38 |        122        1.22       58.77
         39 |         99        0.99       59.76
         40 |         74        0.74       60.50
         41 |         77        0.77       61.27
         42 |         50        0.50       61.77
         43 |         46        0.46       62.23
         44 |         27        0.27       62.50
         45 |         36        0.36       62.86
         46 |         14        0.14       63.00
         47 |         12        0.12       63.12
         48 |          8        0.08       63.20
         49 |          6        0.06       63.26
         50 |          6        0.06       63.32
         51 |          5        0.05       63.37
         52 |          5        0.05       63.42
         53 |          1        0.01       63.43
         54 |          4        0.04       63.47
         55 |          3        0.03       63.50
         56 |          4        0.04       63.54
         57 |          4        0.04       63.58
         58 |          2        0.02       63.60
         60 |          3        0.03       63.63
         61 |          1        0.01       63.64
         62 |          2        0.02       63.66
         66 |          2        0.02       63.68
         99 |      3,632       36.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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