infected by HIV in a pandemic that was affecting most of southern Africa. Land redistribution re-emerged as the main issue for the ZANU–PF government around 1997. Despite the existence of a "willing-buyer-willing-seller" land reform programme since the 1980s, the minority white Zimbabwean population of around 0.6% continued to hold 70% of the country's most fertile agricultural land. In 2000, the government pressed ahead with its Fast Track Land Reform programme, a policy involving compulsory land acquisition aimed at redistributing land from the minority white population to the majority black population. Confiscations of white farmland, continuous droughts, and a serious drop in external finance and other support led to a sharp decline in agricultural exports, which were traditionally the country's leading export-producing sector. Some 58,000 independent black farmers have since experienced limited success in reviving the gutted cash crop sectors through efforts on a smaller scale. President Mugabe and the ZANU–PF party leadership found themselves beset by a wide range of international sanctions. In 2002, the nation was suspended from the Commonwealth of Nations due to the reckless farm seizures and blatant election tampering. The following year, Zimbabwean officials voluntarily terminated its Commonwealth membership. In 2001, the United States enacted the Zimbabwe Democracy and Economic Recovery Act (ZDERA). It came into effect in 2002 and froze credit to the Zimbabwean government. The bill was sponsored by Bill Frist and co-sponsored by U.S. senators Hillary Clinton, Joe Biden, Russ Feingold, and Jesse Helms. Through ZDERA Section 4C ("Multilateral Financing Restriction"), the Secretary of the Treasury is ordered to direct U.S. Directors at the International Financial Institutions listed in Section 3 "to oppose and vote against-- (1) any extension by the respective institution of any loan, credit, or guarantee to the Government of Zimbabwe; or (2) any cancellation or reduction of indebtedness owed by the Government of Zimbabwe to the United States or any international financial institution." By 2003, the country's economy had collapsed. It is estimated that up to a quarter of Zimbabwe's 11 million people had fled the country. Three-quarters of the remaining Zimbabweans were living on less than one U.S. dollar a day. Following elections in 2005, the government initiated "Operation Murambatsvina", an effort to crack down on illegal markets and slums emerging in towns and cities, leaving a substantial section of urban poor homeless. The Zimbabwean government has described the operation as an attempt to provide decent housing to