You need to wrap your code in <code> and </code> tags. The characters [ and ] are special to perl monks and can't put put as literal text in your post. You should also use <p> and </p> tags around paragraphs.

A general tip is to put

use strict;
use warnings;
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Assuming I've understood your problem then this does what you want.

my @data = get_data(); # or however you get them
my %count;
foreach my $datum (@data) {
    ++$count{$datum};
};
foreach my $item_count ( values %count ) {
    $item_count *= 100/@data;
}
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