Unique Year from XSL

uniqueyear.xsl

    <xsl:key name="myYear" match="/IRXML/NewsReleases/NewsCategory/NewsRelease" use="substring(Date/@Date,1,4)"/>
    
    <xsl:template name="yearDropDown">
    	<xsl:for-each select="/IRXML/NewsReleases/NewsCategory/NewsRelease[generate-id() = generate-id(key('myYear',substring(Date/@Date,1,4))[1])]">
        <xsl:sort select="Date/@Date" data-type="text" order="descending" />
        	<xsl:value-of select="generate-id()"/> | 
        	<xsl:value-of select="Date/@Date"/><br />
        </xsl:for-each>
    </xsl:template>