Declare variables referenced in enterframe at function or class level?

[keyboardass]

Hi,

If i have a series of variables that are referenced on an enter frame function, is it better to declare the frequently used vars at the class level? Is there a performance benefit? What is the standard?

Example

public class Animation extends Sprite{

  private var num:int;

  public function Animation(){
  }

  private function happensOnEnterFrame():void{
    num = transformation
    // do other things with num...
  }

} 

...as opposed to...

public class Animation extends Sprite{

  public function Animation(){
  }

  private function happensOnEnterFrame():void{
    var num:int
    num = transformation
    // do other things with num...
  }

}