By John S. McClenahen Americans claim they're worried about the economy, particularly about jobs. But they're spending as if they aren't worried all that much. Personal consumption expenditures increased 0.8% in August to a seasonally adjusted annual rate of $7.78 trillion, the U.S. Commerce Department reported on Sept. 29. Last month was the fourth consecutive month that personal outlays have increased, although August's advance was just under July's 0.9% increase. "The tax cut likely underpinned spending," says UBS Investment Research, New York.