XSTL - Help / Easy one!

How can I remove the "trailing coma" on this XSLT output
with our using an "if" statement: 

  XSLT:
  <xsl:template match="Portfolio/Stock">
	<xsl:apply-templates select="Symbol"/>,
  </xsl:template>


  Output: 
  BA, BA, AAA, BBB, 

  Input:
  <Root>
    <Portfolio>
	<Stock>BA</Stock>
	<Stock>BA</Stock>
	<Stock>AAA</Stock>
	<Stock>BBB</Stock>
    </Portfolio>
  </Root>

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list