Crude oil prices gave up 10 cents over the weekend, slipping to $85.97 a barrel on the New York Mercantile Exchange Monday morning. Gasoline prices gained 2.58 cents to $2.725 a gallon. Home heating oil rose 0.36 cents to $3.0091. Natural gas prices added 1.4 cents to reach $3.517 per million British thermal units. At the pump, the national average price of unleaded gasoline fell to $3.437 per gallon from Sunday\'s $3.439, AAA said. In a report unlikely to affect prices in the short term, the International Energy Agency\'s \"World Energy Outlook\" report released Monday said the United States by 2035 will reach self-sufficiency in terms of net imports and exports of natural gas and oil.