Query: When did Murdoch begin expanding into the U.S?
Context: An extensive advertising campaign on the ITV network in this period, voiced by actor Christopher Timothy, may have helped The Sun to overtake the Daily Mirror's circulation in 1978. Despite the industrial relations of the 1970s – the so-called "Spanish practices" of the print unions – The Sun was very profitable, enabling Murdoch to expand his operations to the United States from 1973.