United States involvement in Chilean affairs intensified in the early decades of the 20th century. After World War I, the United States replaced Britain as the leading superpower controlling most of Chile's resources, as most economic activity in the country lay in US hands. Such a change prevented Chile from profiting as a result of the war and gaining its financial independence. The dependence on the United States formally began in the early years of the 1920s as two major US companies Anaconda and Kennecott took control of the valuable resources. Up until the 1970s, "both industries controlled between 7% to 20% of the country's Gross Domestic Product".