I have a funny joke about this:
A man was writing a book on tithing in the church, and wanted to know how each religion deciphered how much the church received and how much the pastor would get. Well, he interviewed a priest, a southern baptist preacher and a rabbi. The priest walked in, and the author asked, "How do you decide how much you get, and how much the church gets?" The priest said, "Well, I draw a circle in the middle of the floor and I take the money and throw it in the air... Whatever lands in the middle of the circle the church gets, and whatever lands outside the circle, I get." The author writes it down, and the southern baptist preacher walks in, and the author once again asked, "How do you decide how much you get, and how much the church gets?" The preacher said, "Well, I draw a line in the middle of the floor, and I throw the money up... What lands on the left side of the line the church gets and what lands on the other side, I get." The author wrote that down and the rabbi walks in. The author once again asked, "How do you decide how much money you get, and how much the church gets?" The rabbi looks at the author, and says... "Well, I take the money in my hand, say a prayer, throw the money up and whatever God needs I figure he'll grab, and I'll take whatever hits the floor."