At $610 billon for 2014, U.S. military expenditures are 45 percent higher than they were before the Sept. 11, 2001 terror attacks, and more than the next seven top-spending nations combined, according to a new report by the Stockholm International Peace Research Institute (SIPRI).

U.S. military expenditures "dropped by 6.5 per cent in 2014, largely as a result of budget deficit control measures put in place by the US legislature under the 2011 Budget Control Act. U.S. military spending is expected to fall again in 2015 but at a slower rate," the report said.

China was the second-biggest spender, at $216 billion, a 167 percent increase from 2005. Third was Russia, at $84.5 billion, a 97 percent increase in the same period. The U.S., on the other hand, decreased its spending by 20 percent since its highest peak in 2010, according to SIPRI.

Globally, military expenditures were at approximately $1.8 trillion in 2014, a 0.4 percent decrease from 2013 and a 1.7 percent drop from its peak in 2011.

When it comes to military spending as a share of a country's gross domestic product, Saudi Arabia placed first, spending 10.4 percent of its GDP, or $84.5 billion, mostly spent buying U.S. weapons including state-of-the-art F-15 fighters and attack helicopters.

The UAE spent 5.1 percent of its GDP, Russia spent 4.5 percent, and the U.S. spent 3.5 percent.

As The New York Times notes, the wars in the Middle East have been particularly lucrative for American contractors.

"To wage war in Yemen, Saudi Arabia is using F-15 fighter jets bought from Boeing. Pilots from the United Arab Emirates are flying Lockheed Martin's F-16 to bomb both Yemen and Syria. Soon, the Emirates are expected to complete a deal with General Atomics for a fleet of Predator drones to run spying missions in their neighborhood," wrote the Times. "Last week, defense industry officials told Congress that they were expecting within days a request from Arab allies fighting the Islamic State - Saudi Arabia, the Emirates, Qatar, Bahrain, Jordan and Egypt - to buy thousands of American-made missiles, bombs and other weapons, replenishing an arsenal that has been depleted over the past year."

In Ukraine, the crisis has resulted in a push for NATO countries to increase their military spending by at least 2 percent of their GDP, according to a supplemental report provided by SIPRI.

Vice President Joe Biden told Ukrainian President Petro Poroshenko on Monday that the U.S. will be supplying his country with nearly $18 million in additional aid to help provide shelter, food vouchers, potable water and health and sanitation to people affected by the fighting between pro-Russian rebels and Ukrainian government forces, reported The Associated Press. Biden also said the U.S. is prepared to provide loan guarantees worth $1 billion.

An Obama administration official said in March that the U.S. will also provide an additional $75 million in non-lethal equipment, such as drones, Humvees, radios and medical equipment.