According to a survey by the University of Michigan, U.S. consumers are more optimistic about the economy than at any other time in the past eight years, thanks to continued improvement of jobs data and falling gas prices. The survey found that consumer sentiment had jumped to 93.6 in December 2014, up from 88.8 in November, the highest rating since January 2007, nearly a year before the Great Recession officially began.The improved sentiment was evident across age groups, income levels and regions, the survey found. Half the respondents expect the U.S. to avoid a recession in the next five years, the most in a decade.