WASHINGTON (AP) -- Americans spent at the weakest pace in 20 months, a sign that gas prices are taking a toll on the economy. Consumer spending was unchanged in May, the Commerce Department said Monday. That was the worst result since September 2009. And when adjusted for inflation, spending actually dropped 0.1 percent. April's consumer spending figures were revised to show a similar decline when adjusting for inflation. That marked the first declines in inflation-adjusted spending since January 2010. Incomes rose 0.3 percent for the second straight month. But adjusted for inflation, after-tax incomes increased only 0.1 percent in May,...