Japan’s economy has declined at an annualized rate of 1.8% in the July-September period, as President Donald Trump’s tariffs sent the nation’s exports reeling downward. Government data Monday shows that, on a quarter-by-quarter basis, Japan’s gross domestic product, or GDP, or the sum value of a nation’s goods and services, slipped 0.4%, in the first contraction in six quarters. The annualized rate shows what the economy would have done if the same rate were to continue for a year. The market expected a 0.6% drop. A big drop came in exports, which were 1.2% down from the previous quarter.