function change(jahr){
	if(document.getElementById("year_"+jahr).style.display == "none"){
		document.getElementById("year_"+jahr).style.display = "inline";
	}else{
		document.getElementById("year_"+jahr).style.display = "none";
	}	
}

function select_all(){
	for(i=5;i<=13;i++){
		document.getElementById('stufe'+i).checked = true;	
	}	
}

function unselect_all(){
	for(i=5;i<=13;i++){
		document.getElementById('stufe'+i).checked = false;	
	}	
}