foreach my $x_label (sort keys %hash_data){
        foreach my $uri (keys %{$hash_data{$x_label}}){
                print "x: $x_label - value: $hash_data{$x_label}{$uri} ($uri)\n";
        }
}

##</code><code>##

x: 08:57 - value: 178 (http://some.url.com/2011/07/22/link.jhtm)
x: 09:02 - value: 399 (http://some.url.com/2011/07/22/link.jhtm)
x: 09:07 - value: 375 (http://some.url.com/2011/07/22/link.jhtm)
x: 09:07 - value: 371 (http://other.url.com/link.jhtm)
x: 09:12 - value: 358 (http://some.url.com/2011/07/22/link.jhtm)
x: 09:12 - value: 35 (http://other.url.com/2011/07/22/link.jhtm)
x: 09:17 - value: 373 (http://other.url.com/link.jhtm)
x: 09:22 - value: 369 (http://other.url.com/link.jhtm)
x: 09:22 - value: 848 (http://another.url.com/permalink)
x: 09:22 - value: 789 (http://some.url.com/2011/07/22/link.jthm)