Cross-border trade in goods and services is defined by the OCDE as the transactions in goods and services between residents and non-residents. It is measured in USD, as a percentage of GDP for net trade (the value of exports minus the value of imports), and also in annual growth for imports and exports. Cross-border trade in services, which exploded in recent decades, records the value of services exchanged between residents and non-residents of an economy, including services provided through foreign affiliates established abroad. Services include transport, travel, communications services, construction services, insurance and financial services, computer and information services, and others . The World Trade Organization (WTO) issues regular forecasts for cross-border trade patterns and growth rates. These forecasts are partly based on the price of copper, a widely recognised leading indicator of economic activity. Arguably, the EUR-USD exchange rate, embedded in so many commercial contracts, is another market-based indicator that is useful in predicting trends in cross-border trade.