Comecon and the loss of its traditional trading partners, Vietnam was forced to liberalize trade, devalue its exchange rate to increase exports, and embark on a policy of economic development. Between 1975 and 1994, the United States imposed a trade embargo on Vietnam, forbidding any trade during the 19-year period. In 1986, Vietnam launched a political and economic renewal campaign (Đổi Mới) that introduced reforms to facilitate the transition from a centralized economy to a "socialist-oriented market economy". Đổi Mới combined government planning with free-market incentives and encouraged the establishment of private businesses and foreign investment, including foreign-owned enterprises. Furthermore, the Vietnam government stressed the necessity to lower birth rates when developing the economic and social rights of the population by implementing a policy that restricted the number of children per household to two, called the two-child policy. By the late 1990s, the success of the business and agricultural reforms ushered in under Đổi Mới was evident. More than 30,000 private businesses had been created, the economy was growing at an annual rate of more than 7%, and poverty was nearly halved. Throughout the 1990s, exports increased by as much as 20% to 30% in some years. In 1999, exports accounted for 40% of GDP, an impressive performance in the midst of the economic crisis that hit other countries in Asia. Vietnam became a member of the World Trade Organization (WTO) in 2007, which freed Vietnam from textile quotas enacted worldwide as part of the Multi Fibre Arrangement (MFA) in 1974. The MFA placed restrictions on the import by industrialized countries of textiles from developing countries. For China and other WTO members, however, textile quotas under the MFA expired at the end of 2004 as agreed in the Uruguay Round of trade negotiations in 1994. A 2019 study found that Vietnam's WTO entry led to substantial gains in productivity for private firms, but had no impact on state-owned enterprises. In the absence of state-owned enterprises, "the overall productivity gains would have been about 40% larger in a counterfactual Vietnamese economy." Development since 1997 Vietnam's economic policy following the 1997 Asian Financial Crisis has been a cautious one, emphasizing macroeconomic stability rather than growth. While the country shifted toward a more market-oriented economy, the Vietnamese government still continues to hold a tight rein over major state sectors, such as the banking system, state-owned enterprises and foreign trade. GDP growth fell to