XML attribute: how to list values without duplicates

Using the XML below as an example, how would I list all the available countries, but without duplicates. Same for the “industry” attribute. I’m using MX 2004, btw.

<clientlist>
<item industry="retail" country="us">
<client>Albertsons Inc / Boise, ID</client>
<URL>http://www.albertsons.com</URL>
</item>
<item industry="business" country="canada">
<client>Albert Normandin Photography / Vancouver, BC</client>
<URL>http://www.albertnormandin.com</URL>
</item>
<item industry="business" country="israel">
<client>Amdocs Limited / Ra'anana, Israel</client>
<URL>http://www.amdocs.com</URL>
</item>
<item industry="education" country="greece">
<client>American College of Thessaloniki / Thessaloniki, Greece</client>
<URL>http://www.anatolia.edu.gr</URL>
</item>
<item industry="retail" country="canada">
<client>Meinhardt Fine Foods / Vancouver, BC</client>
<URL></URL>
</item>
<item industry="nonprofit" country="us">
<client>WITS / Chicago, IL</client>
<URL></URL>
</item>
<item industry="infocom" country="uk">
<client>XPO Networks Limited / London, UK</client>
<URL></URL>
</item>
</clientlist>

I’m attaching a file to mess around with if anyone cares.