making div section with xsl invisible

In my xsl template I have the following code snippet.

<div style="visibility:hidden">
  <tr>
     <td>
       Total number: <xsl:value-of select="$foo"/>
     </td>
  </tr>
</div>

When I render the page this div section still appears.  I also tried using
the following with the same reuslts.

<div><xsl:attribute name="style">visibility:hidden</xsl:attribute>

Am I missing something simple here?

Thanks