The Alaska Permanent Fund is a constitutionally authorized appropriation of oil revenues, established by voters in 1976 to manage a surplus in state petroleum revenues from oil, largely in anticipation of the recently constructed Trans-Alaska Pipeline System. The fund was originally proposed by Governor Keith Miller on the eve of the 1969 Prudhoe Bay lease sale, out of fear that the legislature would spend the entire proceeds of the sale (which amounted to $900 million) at once. It was later championed by Governor Jay Hammond and Kenai state representative Hugh Malone. It has served as an attractive political prospect ever since, diverting revenues which would normally be deposited into the general fund.

Answer this question, if possible (if impossible, reply "unanswerable"): Why did Governor Keith Miller propose the Alaska Permanent Fund after the Prudhoe Bay sale?
unanswerable