Paul,
Gall bladder function is measured in terms of percentage of ejection and fraction. If the percentage of this contraction is less than 35% then the gall bladder is said to have impaired function. So more than 35% contraction is considered as normal.
As you are having symptoms of gallbladder disease I would suspect your Dr. would recommend the removal of your gallbladder. I had mine removed many years ago and it cured the nagging pain that was with me throughout the day/night especially after meals.
Good luck and keep us posted.
Kindly,
Kitt