#!/usr/bin/env perl -l

use strict;
use warnings;

use XML::LibXML;

my $xml_file = 'pm_1149767_xml_parse.xml';
my $parser = XML::LibXML::->new();
my $doc = $parser->load_xml(location => $xml_file);
my $re = qr{%([^%]+)%};

for ($doc->findnodes('//span/text()')) {
    print $1 while /$re/g;
}