This sends a negative message. China’s exports suffered their biggest drop in seven years, plunging more than 20 percent in February compared to a year earlier. This, combined with import figures falling for the 16th straight month, reflects how the world’s biggest goods trader is suffering in major global markets. Beijing is enduring its slowest rate of growth in 25 years. Investors are growing increasingly wary of the slowdown, which is adding further jitters to already nervous world markets, commodities and international currencies.