The Trucial States of the Persian Gulf coast granted the UK control of their defense and foreign affairs in 19th century treaties. In 1971, six of these states - Abu Dhabi, 'Ajman, Al Fujayrah, Ash Shariqah, Dubayy, and Umm al Qaywayn - merged to form the United Arab Emirates (UAE). They were joined in 1972 by Ra's al Khaymah. The UAE's per capita GDP is on par with those of leading West European nations. For more than three decades, oil and global finance drove the UAE's economy. In 2008-09, the confluence of falling oil prices, collapsing real estate prices, and the international banking crisis hit the UAE especially hard. The UAE did not experience the "Arab Spring" unrest seen elsewhere in the Middle East in 2010-11, partly because of the government's multi-year, $1.6-billion infrastructure investment plan for the poorer northern emirates, and its aggressive pursuit of advocates of political reform. The UAE in recent years has played a growing role in regional affairs. In addition to donating billions of dollars in economic aid to help stabilize Egypt, the UAE was one of the first countries to join the Defeat-ISIS coalition, and is a key partner in a Saudi-led military campaign in Yemen.