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

my @data = [
   '17-02-2005','18-02-2005','19-02-2005',
   '20-02-2005','21-02-2005','22-02-2005',
   '23-02-2005','24-02-2005'
];

my %labels = (
   'C' => [0,0,0,0,7,0,0,2],
   'A' => [0,0,0,0,0,0,5,4],
   'B' => [0,0,0,0,0,0,0,0]
);

foreach my $item (sort {$a cmp $b} keys %labels) {
   #       replaced
   #push @{$data[$item]}, $labels{$item};   
   #         with
   push @{$data[0]}, $labels{$item};
}

use Data::Dumper;
print Dumper @data;