function showPR(yr) {
    var yearUL = "pr" + yr;
    var yearBullet = "bullet" + yr;
        
    var yearList = document.getElementById(yearUL);
    var yearBullet = document.getElementById(yearBullet);
    if (yearList.style.display == "none") {
        yearList.style.display = "block";
        yearBullet.className = "press_releases_up";
    } else {
        yearList.style.display = "none";
        yearBullet.className = "press_releases_down";
    }
     
}