Syntax for itemprop breadcrumb

In breadcrumb display, the unlinked current page or section is often displayed in the same line as the linked parents.  E.g.:

<div><a href="/">Home</a> | About us</div>

Should this unlinked portion be ("About us" in the example above) be included in the breadcrumb itemprop or excluded from it? 1 or 2 below?


1 - Unlinked portion part of breadcrumb itemprop

<div itemprop="breadcrumb">
  <a href="category/books.html">Books</a> >
  <a href="category/books-literature.html">Literature & Fiction</a> >
  <a href="category/books-classics">Classics</a> >
  Boring Classics
</div>

2 - Unlinked portion not a part of breadcrumb itemprop

<div>
<span itemprop="breadcrumb">
  <a href="category/books.html">Books</a> >
  <a href="category/books-literature.html">Literature & Fiction</a> >
  <a href="category/books-classics">Classics</a></span> >
  Boring Classics
</div>

None of the schema.org examples show this use case.

See also this same question on a G+ post - feel free to comment there.
https://plus.google.com/106943062990152739506/posts/Bf5ZYWkVtM1

Thanks,
Aaron