Dear Experts

I have followin codes


CSS

#footer {
	clear:both;
  width: 826px;
  height: 50px;
  background: rgb(0%, 80%, 40%);
  padding: 5px;
  margin: 0;
line-height: 50px;
}

HTML

<div id="footer">
Last Updated : January 01, 2012
  </div>

Footer tags is included in all 5 pages, When I update any page then I have to edit this line

Last Updated : January 01, 2012

in all pages

Is there a way to create variable to store last updated value.
Then this value must show in the footer div of every page.

Please help