Taxonomy Field Order

Hi,

I have a simple taxonomy field named "Grade Level" with the following choices:

<ul>
	<li>Pre-K</li>
	<li>Elementary</li>
	<li>Middle School</li>
	<li>High School</li>
	<li>Post Secondary</li>
</ul>

This field is being displayed as a checkbox list. In the checkbox list the choices are being ordered by title, alphabetically ascending, so the order is incorrect:

<ul style="list-style-type:square">
	<li>Elementary</li>
	<li>High School</li>
	<li>Middle School</li>
	<li>Post Secondary</li>
	<li>Pre-K</li>
</ul>

How can I order by ID instead? Thank you.