And of course you can also use XML::Twig to get the same result:

#!/bin/perl -w

use strict;
use XML::Twig;

my $posts= 0;
my $rep=0;

my $twig= new XML::Twig( TwigRoots => 
            { NODE => sub { my( $t, $node)= @_;
                            $posts++; 
                            $rep +=$_[1]->att( 'reputation'); 
                            $t->purge;
                          }
            });

$twig->parsefile( $ARGV[0]);
print "$posts posts, $rep rep, ", sprintf( "%5.2f", $rep/$posts),  " a
+verage\n";
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