Suppose that a worker in Freedom can produce either 6 units of corn or 2 units of wheat per year, and a worker in Liberty can produce either 2 units of corn or 6 units of wheat per year. Each nation has 10 workers. For many years the two countries traded, each completely specializing in producing the grain for which it has a comparative advantage. Now, however, war has broken out between them and all trade has stopped. Without trade, Freedom produces and consumes 30 units of corn and 10 units of wheat per year. Liberty produces and consumes 10 units of corn and 30 units of wheat. By how much has the combined yearly output of the two countries declined?