How to use Resolution.refreshRate?

Hi, so I am making a game for web players and I want to display the refresh rate of the monitor in the options menu, and I've already made it so that I can see the width and the height, but I just don't know how to use Resolution.refreshRate because it always returns an error saying something that it's trying to access a non-static member or whatever.

Here's my script:

 var Text : TextMesh;
 
 var x;
 
 var y;
 
 var rate;
 
 function Update () {
 
 x = Screen.width;
 
 y = Screen.height;
 
 rate = Resolution.refreshRate;
 
 Text.text = "Resolution: " + x + "x" + y + " @ " + rate;
 
 }