Takes one optional parameter, the year-number. Prefix it with a minus sign for BC.

For AD years the number can be omitted if it is the page name.

The box width shrinks nearly 6% for smaller year-number sizes.

Example for "{{Year nav|2013}}" at right:
Millennium:
Centuries: – '
Decades:       – –      
Years: – '
Example for "{{Year nav|13}}" at right:
Millennium:
Centuries: – '
Decades:       – –      
Years: – '
Example for "{{Year nav|2061}}" at right:
Millennium:
Centuries: – '
Decades:       – –      
Years: – '
Example for "{{Year nav|-817}}" at right:
Millennium:
Centuries: – '
Decades:       – –      
Years: – '