How to tell if a button is held down?

I have this code

     if (GUI.Button(new Rect(0, 0, 200, 200), "CLICK " + counter))
        {
            counter++;
        }

What I want to happen is when the input device(Mouse/Finger) presses and holds the button down, the counter goes up , instead of having the counter go up each time it is pressed and released, but instead just held down. Can this be done?

Thanks

Does GUI.RepeatButton sort it out for you?

Thanks that is exactly what i wanted