It should load the current year based on the server's date. It can provide a different year if you provide a date as an argument, but the way you've written it should just show the current year.
Just make sure PHP is installed to the server displaying the web page. That code is often used for copyright dates.
Yes this code load the current Year and write result also see below with function : <?php echo date("y"); ?> Short Year 11 <?php echo date("Y"); ?> Full year 2011
This is PHP, not HTML. You have already been given the answer but here you will find all arguments that can be passed through the date function: http://php.net/date