Genesis 41:34
Let Pharaoh do this, and let him appoint officers over the land, and take up the fifth part of the land of Egypt in the seven plenteous years.
Genesis 47:24
And it shall come to pass in the increase, that ye shall give the fifth part unto Pharaoh, and four parts shall be your own, for seed of the field, and for your food, and for them of your households, and for food for your little ones.
Genesis 47:26
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.