estimated to be 14% for people aged 15–49 in 2009. UNESCO reported a decline in HIV prevalence among pregnant women from 26% in 2002 to 21% in 2004. By 2016 HIV/AIDS prevalence had been reduced to 13.5% compared to 40% in 1998. At the end of November 2008, some operations at three of Zimbabwe's four major referral hospitals had shut down, along with the Zimbabwe Medical School, and the fourth major hospital had two wards and no operating theatres working. Those hospitals still open were not able to obtain basic drugs and medicines. The situation changed drastically after the Unity Government and the introduction of the multi-currency system in February 2009 although the political and economic crisis also contributed to the emigration of the doctors and people with medical knowledge. In August 2008 large areas of Zimbabwe were struck by the ongoing cholera epidemic. By December 2008 more than 10,000 people had been infected in all but one of Zimbabwe's provinces, and the outbreak had spread to Botswana, Mozambique, South Africa and Zambia. On 4 December 2008 the Zimbabwe government declared the outbreak to be a national emergency and asked for international aid. By 9 March 2009 The World Health Organization estimated that 4,011 people had succumbed to the waterborne disease since the outbreak began, and the total number of cases recorded had reached 89,018. In Harare, the city council offered free graves to cholera victims. Education Large investments in education since independence has resulted in the highest adult literacy rate in Africa which in 2013 was 90.70%. This is lower than the 92% recorded in 2010 by the United Nations Development Programme and the 97.0% recorded in the 2002 census, while still substantially higher than 80.4% recorded in the 1992 census. The wealthier portion of the population usually send their children to independent schools as opposed to the government-run schools which are attended by the majority as these are subsidised by the government. School education was made free in 1980, but since 1988, the government has steadily increased the charges attached to school enrolment until they now greatly exceed the real value of fees in 1980. The Ministry of Education of Zimbabwe maintains and operates the government schools, but the fees charged by independent schools are regulated by the cabinet of Zimbabwe. The education department has stated that 20,000 teachers have left Zimbabwe since 2007 and that half of