As alternative, and if your input get some complex, I would use a hash of hashes, with a "fixed field name" before every field. In the follow example I will use an extra final key, so every value could have some attributes to keep

Of course if you need program a "program" and not a cheap script, then probably you should use object orientation (perlobj)

The idea would be to have:

#!/usr/bin/perl -w
use strict;

my %data;

while (<DATA>)
{
    chomp;
    my ($number, $value) = split;
    $data{number}{$number}{value}{$value}{metric1}||=0;
    $data{number}{$number}{value}{$value}{metric1}++;
}

foreach my $n (keys %{$data{number}})
{
    foreach my $v (keys %{$data{number}{$n}{value}})
    {
        print $v." (".$data{number}{$n}{value}{$v}{metric1}." times)\n
+";
    }
}
__DATA__
1 AAA
2 BBB
3 CCC
4 DDD
2 EEE 
2 EEE
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