LONDON — The United States is slipping and emerging markets are improving, but European economies still dominate the list of the most competitive economies in the world, according to a World Economic Forum report released Wednesday.

For the third consecutive year, Switzerland ranked first in the forum’s annual competitiveness survey, which assesses countries based on 12 categories including innovation, infrastructure and the macroeconomic environment.

The United States, which topped the list in 2008, continued its decline, also for the third year in a row, falling one place to fifth. The weaker performance was attributed to economic vulnerabilities as well as “some aspects of the United States’ institutional environment,” notably low public trust in politicians and concerns about government inefficiency.

Singapore overtook Sweden to claim the second position. But perhaps surprisingly, given the crisis of confidence that continues to plague the European financial system, Western European countries dominated the survey’s top 10 economies.