country. As of 2017, more than one-quarter of the adult population was infected by HIV/AIDS; Eswatini has the world’s highest HIV prevalence rate, a financial strain and source of economic instability. The manufacturing sector diversified in the 1980s and 1990s, but manufacturing has grown little in the last decade. Sugar and soft drink concentrate are the largest foreign exchange earners, although a drought in 2015-16 decreased sugar production and exports. Overgrazing, soil depletion, drought, and floods are persistent problems. Mining has declined in importance in recent years. Coal, gold, diamond, and quarry stone mines are small scale, and the only iron ore mine closed in 2014. With an estimated 28% unemployment rate, Eswatini's need to increase the number and size of small and medium enterprises and to attract foreign direct investment is acute. Eswatini's national development strategy, which expires in 2022, prioritizes increases in infrastructure, agriculture production, and economic diversification, while aiming to reduce poverty and government spending. Eswatini's revenue from SACU receipts are likely to continue to decline as South Africa pushes for a new distribution scheme, making it harder for the government to maintain fiscal balance without introducing new sources of revenue.