How to automatically add raquo to li elements using CSS

Question

I want to automatically add the HTML character » (») to the left of each li element.

What would be the best practise?

I want the HTML to be:

<ul>
  <li>item 1</li>
  <li>item 2</li>
  <li>item 3</li>
</ul>

And it should display:

» item 1
» item 2
» item 3