#!perl
use strict;
use HTML::Treebuilder::XPath;

my $URL = 'http://www.treasurydirect.gov/xml';
my $tree = HTML::TreeBuilder::XPath->new_from_url($URL);
my @file = $tree->findnodes_as_strings('//li/a[contains(@href,"CPI_")]');
my $latest = ( sort @file )[-1];
print "Latest = $latest";