 However, the Welsh tinplate industry was dependent on exporting to the American market, and suffered serious implications from the imposition of the McKinley tariff in 1890.By the end of the Second World War the traditional local heavy industries were in decline, and although Swansea Bay emerged as a major centre of the petroleum industry in the 1960s, Swansea shared in the general trend towards a post-industrial, service sector economy.Today, the most important economic sectors in the City and County of Swansea are