date:year
Returns the year of a date as a number. If no argument is given, then the current local date/time, as returned by date:date-time is used as the default argument.
year($date-time as string?) ➔ number
| Arguments | |||
| 
 | $date-time | string? | The input date/time | 
| Result | number | ||
Namespace
http://exslt.org/dates-and-times