Part of this splurge can be attributed to Saudi Arabia's entanglement in a costly war in Yemen, which has raged for more than a year now. Since 2006, Saudi annual military spending has nearly doubled. That figure is roughly the same, too, for Russia.
But, as SIPRI's report notes, the drop in oil prices worldwide has otherwise had huge effects on arms sales in general.
"Saudi Arabia overtook Russia to become the third-largest spender, mainly due to the fall in the value of the rouble," it noted. The two most dramatic dips in military expenditure were in Venezuela, where it decreased by 64 percent, and Angola, whose spending dropped by more than 40 percent. Both countries' economies are dependent on oil exports.
Meanwhile, Asia's militarization proceeded apace — spending in the region rose 5.4 percent in 2015, largely as a consequence of China's ongoing build-up and the increased wariness of neighbors, such as Vietnam and the Philippines.
"Military spending in 2015 presents contrasting trends," said Sam Perlo-Freeman, head of SIPRI’s military expenditure project, in a statement. "On the one hand, spending trends reflect the escalating conflict and tension in many parts of the world; on the other hand, they show a clear break from the oil-fueled surge in military spending of the past decade. This volatile economic and political situation creates an uncertain picture for the years to come."
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