diff --git a/graph-scroll.js b/graph-scroll.js
index 7948e36..90c9701 100644
--- a/graph-scroll.js
+++ b/graph-scroll.js
@@ -37,6 +37,13 @@ function graphScroll() {
       isFixed = isFixed1
       graph.classed('graph-scroll-fixed', isFixed)
     }
+    
+    var pos = pageYOffset - 10 - containerStart;
+    var prevTop = sectionPos[i];
+    var nextTop = (i+1<sectionPos.length?sectionPos[i+1]:(belowStart-containerStart)) - 200 ;
+    var progress = (pos - prevTop) / (nextTop - prevTop);
+    if(progress>=0 && progress <=1)
+      dispatch.scroll(i, progress);
   }
 
   function resize(){