of British households had no inside toilet, while in 1967 22% of all homes had no basic hot water supply. By the 1990s, most homes had these amenities together with central heating. From 1996–1997 to 2006–2007, real median household income increased by 20% while real mean household incomes increased by 23%. There has also been a shift towards a service-based economy in the years following the end of the Second World War, with 11% of working people employed in manufacturing in 2006, compared with 25% in 1971. Common Market (EEC), then EU, membership Britain's wish to join the Common Market (as the European Economic Community was known in Britain) was first expressed in July 1961 by the Macmillan government. It was vetoed in 1963 by French President Charles de Gaulle. After initially hesitating over the issue, Harold Wilson's Labour Government lodged the UK's second application (in May 1967) to join the Community. Like the first, though, it was vetoed by de Gaulle. In 1973, with DeGaulle gone, Conservative Prime Minister Heath negotiated terms for admission and Britain finally joined the Community. In opposition the Labour Party was deeply divided, though its Leader, Harold Wilson, remained in favour. In the 1974 General Election the Labour Party manifesto included a pledge to renegotiate terms for Britain's membership and then hold a referendum on whether to stay in the EC on the new terms. This was a constitutional procedure without precedent in British history. In the subsequent referendum campaign, rather than the normal British tradition of "collective responsibility", under which the government takes a policy position which all cabinet members are required to support publicly, members of the Government (and the Conservative opposition) were free to present their views on either side of the question. A referendum was duly held on 5 June 1975, and the proposition to continue membership was passed with a substantial majority. The Single European Act (SEA) was the first major revision of the 1957 Treaty of Rome. In 1987, the Conservative government under Margaret Thatcher enacted it into UK law. The Maastricht Treaty transformed the European Community into the European Union. In 1992, the Conservative government under John Major ratified it, against the opposition of his backbench Maastricht Rebels. The Treaty of Lisbon introduced many changes to the treaties of the Union. Prominent changes included more qualified majority voting in the Council of Ministers, increased involvement of the