Template:Year by continent category/doc

Creates a category of the form "YYYY by continent", where YYYY is a 4-digit year.

e.g.
 * Category:1535 by continent
 * Category:1859 by continent
 * Category:1992 by continent

Usage
No parameters needed

Errors
If this template is used on an invalid page, then an error message is displayed, and the page is categorised in a tracking category: Note that this tracking page is shared with other category header templates)
 * Category:Errors reported by other category header templates (population: pages)

Errors include:
 * The page is not in the category namespace
 * The page's title does not take the form "YYYY by continent"