U.S. consumer confidence rose slightly in December despite underlying concerns about the health of the U.S. economy, according to a private report released Thursday. The Conference Board, a business-financed research organization, said its consumer-confidence index rose to 88.6 in December from 87.8 the previous month. It was the first increase since July, and was in contrast to economists' expectation of a decline. The present-situation index, which measures consumer's view of current economic conditions, fell to 108.3 in December, its lowest since October 2005, from 115.7 in November. The expectations index, which measures consumers' outlook over the next six months, rose to 75.5 this month from 69.1 in November. Conference Board director of consumer research Lynn Franco said the gain in the overall index “was due solely to an increase in the expectations index.” “Consumers' short-term outlook regarding business conditions, employment, inflation, and stock prices improved marginally,” Franco said in a statement. However, she added, “Persistent declines in the present-situation index indicate the economy is still losing momentum.” Economists closely watch consumer-confidence reports for clues on consumer spending, which accounts for two-thirds of total U.S. economic activity.