Adding the results of count()

I could use some help taking the results of counting all of the elements in set of documents, then adding all those counts together.

What I've written, of course, creates a text documents that lists the source document and how many graphic elements are in each particular document. My question, how can I take the results of the count and add them up using the sum() function. Or can I even do that?

Of course, I can always open the result document and add them up with a calculator, but I'd like to be a bit more elegant and learn something in the process. Thanks for any assistance.



    <xsl:param name="collection" select="collection('file:/C:/documents/?select=*.xml')"/>
    
    <xsl:template match="/">
        <xsl:result-document method="text" href="file:/C:/results/graphic_Count.txt">
        <xsl:for-each select="$collection">
            <xsl:value-of select="base-uri(.)"/><xsl:text>  ---   </xsl:text>
                <xsl:value-of select="local-name()"/>
                <xsl:value-of select="count(descendant::graphic)"/>
            <xsl:text>&#x0A;</xsl:text>
        </xsl:for-each>
    </xsl:result-document>
  
    </xsl:template>



Charlie