Now, when the hemoglobin travels down to our resting tissue, which is at a pressure of about 40 mercury, the corresponding Y value is about zero point 77. And that means about 77% of that hemoglobin is fully saturated with oxygen inside our resting tissue. Now, what that tells us is when the hemoglobin goes from the lungs to the resting tissue, there is a difference of about 21%. And what that means is 21% of that oxygen of that hemoglobin has successfully unloaded and released the oxygen to the resting cells of our body. So this is how much oxygen can be unloaded by the hemoglobin when it goes from the lungs to the resting tissue. Now, what about if we're exercising?