function change_view (year)
{
  var yeardiv = document.getElementById (year);
  var yearimg = document.getElementById ("img" + year);
  if (yeardiv.style.display == "block") {
    yearimg.src = "/uploads/images/arrow_closed.png";
    yeardiv.style.display = "none";
  } else {
    yeardiv.style.display = "block";
    yearimg.src = "/uploads/images/arrow_expanded.png";
  }
}