Is this clearer to your eye's?

#! perl -slw
use strict;

print "Age\tMale\tFemale";

print for map{ ## And strip out the combined total.
    s[(^\d+\s+)[\d\.]+\s+][$1];
    $_;
    
} sort { ## Sort the lines by age
    local $^W; ## Ignoring non-numeric warnings
    $a <=> $b
    
}  grep{  ## Remove any lines that don't fit the pattern
    m[^\d+\s]
    
} map{ ## Split lines that fit the two column pattern into two
    m[(^\d+\s+(?:[\d\.]+\s+){3})(.+$)]
    
} <DATA>;


__DATA__
Your data here
[download]

Produces

P:\test>501023
Age     Male    Female
0    319.1    303.6
1    316.8    301.2
2    321.6    306.8
...
86    24.0    72.6
87    19.2    61.6
88    15.2    50.9
89    11.6    40.7
[download]