NEW ORLEANS (AP) — Hurricanes Gustav and Ike left behind at least $8 billion in physical damage in Louisiana and the cost already could be as high as $20 billion, a state agency said Thursday.The Louisiana Department of Economic Development included both insured and uninsured losses — and said the number of homes flooded by Ike on the Louisiana coast likely would range from 13,000 to 26,500.For businesses, another $2.5 billion to $5 billion was lost in economic activity from Gustav, which forced mandatory evacuations across southern Louisiana, including the New Orleans metropolitan area, the report said. A figure has yet to be tallied for Ike, which had fewer evacuations.The physical estimate did not include damage to the petroleum producing infrastructure in the Gulf of Mexico. But DED said disrupted oil and natural gas production in the region probably will run in value from $8 billion to $10 billion.According to report, Gustav likely caused $4.5 billion to $10 billion in property damage to Louisiana, including:— $2 billion to $4.5 billion for homes, vehicles and personal property— $1 billion to $2.5 billion for commercial structures, property and inventory— $1.5 billion to $3 billion for damage to agriculture, fisheries, timber, public facilities and infrastructure.DED said the early estimate for property losses from Ike, likely ranging from $3.5 billion to $10 billion, includes:— $2 billion to $5.5 billion for homes, vehicles and personal property— $500 million to $2 billion for commercial structures, property and inventory— $1 billion to $2.5 billion for damage to agriculture, fisheries, timber, public facilities and infrastructure.