diff --git a/README.md b/README.md
index 256e4cce..a1aba131 100644
--- a/README.md
+++ b/README.md
@@ -198,7 +198,7 @@ If *delta* is specified, sets the wheel delta function to the specified function
 
 ```js
 function wheelDelta(event) {
-  return -event.deltaY * (event.deltaMode === 1 ? 0.05 : event.deltaMode ? 1 : 0.002);
+  return -event.deltaY * (event.deltaMode === 1 ? 0.05 : event.deltaMode ? 1 : 0.002) * (event.ctrlKey ? 10 : 1);
 }
 ```