U.S. retail gasoline prices have been declining for weeks, and they could fall farther as autumn arrives, energy experts say. The national average for a gallon (3.8 liters) of unleaded regular gasoline was just above $2.68 on Friday, according to three price-tracking organizations. That price is 6.6 cents below a month ago and 8.5 cents higher than a year ago. The national average has remained below $3 a gallon for almost two years, and most analysts believe it will not return to that psychological level anytime soon. The last time the average retail gasoline prices was at or above $3 a gallon was in October 2008 after a busy summer season when prices surpassed $4 a gallon. The U.S. government reported Friday that the unemployment rate rose in August to 9.6 percent from 9.5 percent the previous several months. High unemployment means fewer commuters driving. Combined with unusually high gasoline supplies and the end of the summer driving season, it also means retail gasoline prices likely will continue to drop. When the U.S. economy showed signs of recovering from the recession this year, experts predicted retail prices would top $3 by late May. But the price peaked at $2.92 a gallon in early May as fears about the pace of the economic recovery intensified and consumers spent less money. While an improving economy with more jobs would be good news, it also could translate into higher fuel prices. Most experts believe oil will have to range between $80 and $100 a barrel before consumers see a $3 per gallon national average. In Friday trading on the New York Mercantile Exchange, light sweet crude oil for October delivery was down nearly $1.50 to about $73.60 a barrel.