Genesis 47:26

So Joseph made it a statute concerning the land of Egypt , and it stands to this day , that Pharaoh should have the fifth ; the land of the priests alone did not become Pharaoh’s .

So Joseph established it as a law concerning land in Egypt—still in force today—that a fifth of the produce belongs to Pharaoh. It was only the land of the priests that did not become Pharaoh`s.

And Joseph made it a law over the land of Egypt unto this day, that Pharaoh should have the fifth part ; except the land of the priests only, which became not Pharaoh's.