It's not a proper question, because it's not "should be" anything. It has to vary continuously all during the day, and pretty well never stay constant. If it doesn't vary, then there's something wrong with you. This is because it directly reflects the varying amount of blood flow (the 'supply') round your body, and this depends on what you're doing, ('demand'). So, (in answer to Alexandia below) it can never be "too close together", because supply is continuously tracking demand, -always trying to close the gap.
What it actually is (mathematically), is the amount of blood your heart pumps out every minute divided by your pulse rate..... (well. -multiplied by your arterial compliance, that is, - to be strictly accurate). they're proportional. So it can't possibly be any steady 'normal' number, can it..?
Unless you're in a coma
And since the amount of blood your heart pumps out varies slightly continually, and your pulse rate varies ever so slightly all the time too, anyone who tells you "it SHOULD be" any special number is talking nonsense.