According to BBC, "measuring carbon monoxide in exhaled breath showed a normal non-smoker's level to be three parts CO per million parts of air (ppm) (less than 1% of blood not working properly), a light smoker to have 10-20 ppm (2-4% of blood not working properly), and a heavy smoker 30-40 ppm (5-7%). The study found shisha smokers had 40-70 ppm of CO in their breath - affecting 8-12% of their blood."
So people, clear your misconceptions.