diff --git a/conllusvg/center-exam.html b/conllusvg/center-exam.html
index efdd1ee34d2813ec1771f83062eb03a89bdeb189..a628c0c8db7acb60daea9c34d949490705a72839 100644
--- a/conllusvg/center-exam.html
+++ b/conllusvg/center-exam.html
@@ -14,7 +14,7 @@ CenterExam.init=function(){
   CenterExam.svg=new Array();
   CenterExam.pre=new Array();
   CenterExam.timer=setTimeout("clearTimeout(CenterExam.timer);CenterExam.checkview()",200);
-  CenterExam.volchange();
+  CenterExam.getyear();
 }
 CenterExam.checkview=function(){
   var t,r,b,i,x;
@@ -136,6 +136,27 @@ CenterExam.buildup=function(x){
     conllusvg.loadRemote("pre"+x,CenterExam.url+"files/"+encodeURIComponent(i)+"/raw?ref=master");
   }
 }
+CenterExam.getyear=function(){
+  if(CenterExam.request==null)
+    CenterExam.request=new XMLHttpRequest();
+  CenterExam.request.onload=CenterExam.ongetyear;
+  CenterExam.request.open("GET",CenterExam.url+"tree?per_page=100&path=center-exam");
+  CenterExam.request.send();
+}
+CenterExam.ongetyear=function(e){
+  var i,j,s;
+  if(CenterExam.request.status==200){
+    s=CenterExam.request.responseText;
+    i=s.indexOf("center-exam/19");
+    if(i<0)
+      i=s.indexOf("center-exam/20");
+    j=parseInt(s.substring(i+12,i+16),10);
+    s=document.getElementById("vol");
+    for(i=s[0].value.slice(12)-1;i>=j;i--)
+      s.add(new Option(i+"年","center-exam/"+i));
+  }
+  CenterExam.volchange();
+}
 CenterExam.volchange=function(){
   var s,x;
   CenterExam.clearSVG();
@@ -156,10 +177,9 @@ CenterExam.volchange=function(){
 }
 CenterExam.gettree=function(){
   var p;
-  if(CenterExam.request==null){
+  if(CenterExam.request==null)
     CenterExam.request=new XMLHttpRequest();
-    CenterExam.request.onload=CenterExam.ongettree;
-  }
+  CenterExam.request.onload=CenterExam.ongettree;
   if(CenterExam.tail[CenterExam.volpath]==null)
     p=1;
   else
@@ -254,11 +274,6 @@ CenterExam.gitlab=function(){
 <font size="+3"><b>大学入試センター試験『国語』漢文</b></font><br>
 <select id="vol" onchange="CenterExam.volchange()">
 <option value="center-exam/2019">2019年</option>
-<option value="center-exam/2018">2018年</option>
-<option value="center-exam/2017">2017年</option>
-<option value="center-exam/2016">2016年</option>
-<option value="center-exam/2015">2015年</option>
-<option value="center-exam/2014">2014年</option>
 </select>
 <input type="text" id="count" size=3 value=0 style="text-align:right" onchange="CenterExam.writeSVG()" />
 <input type="button" value="GitLab" onclick="CenterExam.gitlab()" />