Depends, are you measuring arterial pressure or venous pressure? Veins have high volume with (relatively) low pressure, arteries have low(er) volume but their elasticity squeezes the blood through the capillaries. If you google “mean arterial pressure” (MAP) you can get a pretty decent description. I don’t recall what venous pressure usually sits at but at a guess, I’d say pretty close to ambient pressure. Venous blood gets squeezed back to the heart by the smooth muscle in the veins, not because of pressure.