Displaying Sum of Column in Exported file

HTML & CSS
1

Hi i’m working on Visual studio 2010(ASP.NET). and i’m using xsl to export the Grid panel value to excell,and open office and csv…
every thing is working fine but now i want to display the sum of the colum in exported file so please help me to solve this…
here is my code (which is i’m using to export)

<xsl:template match="/*">
  <Worksheet>
  <xsl:attribute name="ss:Name">
  <xsl:value-of select="local-name(/*/*)" />
  </xsl:attribute>
    <Table x:FullColumns="1" x:FullRows="1">
      <Row>
        <xsl:for-each select="*[position() = 1]/*">
          <Cell><Data ss:Type="String">
          <xsl:value-of select="local-name()" />
          </Data></Cell>
        </xsl:for-each>
      </Row>
      <xsl:apply-templates/>
    </Table>
  </Worksheet>
</xsl:template>


<xsl:template match="/*/*">
  <Row>
    <xsl:apply-templates/>
  </Row>
</xsl:template>


<xsl:template match="/*/*/*">
  <Cell><Data ss:Type="String">
    <xsl:value-of select="." />
  </Data></Cell>
</xsl:template>
  
  

</xsl:stylesheet>