$('#yearfilter').parent().append('<ul id="newyearfilter" name="yearfilter"></ul>');
$('#yearfilter option').each(function(){
$('#newyearfilter').append('<li value="' + $(this).val() + '">'+$(this).text()+'</li>');
});
$('#yearfilter').remove();
$('#newyearfilter').attr('id', 'yearfilter');
this is how I would do it.