Americans are changing their holiday shopping habits this year, finds a new survey by consulting firm Deloitte (pdf). According to the annual study, 11.5 percent of Americans will not be spending anything on presents, gift cards, or any other items for entertaining. This is the highest percentage since the company began tracking consumers’ holiday habits. What is driving many Americans to become Scrooge? The top concern for consumers, investors, and voters today: Inflation. Thirty-nine percent of consumers who may spend more this year attribute this to higher prices in general, the survey revealed. Half of the consumers who say they will spend less this year blame it on higher food costs. The survey also highlighted a “tale of two holidays,” with a substantial gap in shopping plans between high- and low-income groups. The holiday retail report found that U.S. households earning an annual income of $100,000 or more will spend …