[xsl] xslt count distinct values - X3D

[j milo taylor <milo@xxxxxxxxxx>]

I need to count the distinct <Country> values from this XML and this to 
be assigned to the 'size'; dattribute of a <Box> element in X3D

The XML (fragment example)/////////////////////////////////////////

<Artists_by_Countries>

   <Artist_by_Country>
       <Location_ID>62</Location_ID>
       <Artist_ID>212</Artist_ID>
       <Country>Argentina</Country>
   </Artist_by_Country>

    <Artist_by_Country>
       <Location_ID>4</Location_ID>
       <Artist_ID>108</Artist_ID>
       <Country>Australia</Country>
   </Artist_by_Country>

    <Artist_by_Country>
       <Location_ID>4</Location_ID>
       <Artist_ID>111</Artist_ID>
       <Country>Australia</Country>
   </Artist_by_Country>

   <Artist_by_Country>
       <Location_ID>12</Location_ID>
       <Artist_ID>78</Artist_ID>
       <Country>Germany</Country>
   </Artist_by_Country>

</Artists_by_Countries>

I've been using this XSLT, but getting nowhere (the Muenchian Method??) 
(using Netbeans)

XSLT///////////////////////////////////////////psuedo

<xsl:key name="artists-by-country" match="Artist_by_Country" 
use="Country" />
..
..
..
   <xsl:template match="Artists_by_Countries">
       <xsl:for-each select="Artist_by_Country[count(. | 
key('artists-by-country', Country)[1]) = 1]">
   <Transform>
       <Shape>
           <Box>
               <xsl:attribute name ='size'>
                 
                   <xsl:value-of=" KEY COUNT OF DISTINCT COUNTRY 
VALUES>    

               </xsl:attribute>
           </Box>
       </Shape>
   </Transform>     
       </xsl:for-each>
</xsl:template>

Please, any help/advice anyonr has would be great. Coming to the end of 
a Phd and my head is exploding!!!

Best regards
Milo