Which number should replace the question mark?

70-year-old George went for his annual physical. He told the doctor that he felt fine, but often had to go to the bathroom during the night. Then he said, But you know Doc, Im blessed. God knows my eyesight is going, so he puts on the light when I pee, and turns it off when Im done!

A little later in the day, Dr. Smith called Georges wife and said, Your husbands test results were fine, but he said something strange that has been bugging me. He claims that God turns the light on and off for him when uses the bathroom at night. Thelma exclaimed, That old fool! Hes been peeing in the refrigerator again!