Whats the average percent of oxygen in the blood? I'm a heavy smoker and when I got checked at triage I had 99percent it said. But scarring in lungs

Quit smoking... A normal oxygen saturation that is measured the way you are talking about is typically greater than 95% in your age range (down to as low as 90% in someone with chronic lung problems). The effects of smoking don't always show up on an oxygen saturation percentage until a chronic lung condition has set in, so don't let that lead you to believe everything is normal. I would advise quitting.