List of all entries of custom-post-type: Add year-parameter?

I’ve modified above function somewhat

function get_event_list( $latest = true, $order="ASC", $return = false, $year ) {
    // Pass year i.e $year
    $enddate = strtotime($year."-12-31"); // year's last date
    $startdate = strtotime( ($year-1)."-12-31"); year's first date

$yesterday = array($startdate, $enddate ); // Fetch posts between these dates
$compare="BETWEEN";// Between above two dates
$current_year="";

$args = array(
    'post_type' => 'wr_event',
    //'posts_per_page' => is_archive() ? 16 : -1,
    'posts_per_page' => -1,
    'meta_key' => 'event_date',
    'orderby' => 'meta_value_num',
    'order' => $order,
    'meta_value' => $yesterday,
    'meta_compare' => $compare,
    /*'tax_query' => array(
        array(
            'taxonomy'  => 'event_type',
            'field'     => 'slug',
            'terms'     => 'empfehlungen',
            'operator'  => 'NOT IN'
            ),
       )*/
);

$loop = new WP_Query( $args );

Its untested but should work. Let me know if it worked or not