The North Atlantic Treaty Organization (NATO) says its greatest responsibility is to prevent conflict and preserve peace. To secure this, the alliance calls on each member to pay their fair share.
NATO's 2018 annual report, which was released on Thursday, showed that several European members had moved closer their pledge of dedicating 2% of their GDP on defence, while others were still lagging behind.
Six European governments now are above the threshold sought by US President Donald Trump — Estonia, Greece, Poland, Latvia, Lithuania and Britain were estimated to have met the 2% goal last year.
Meanwhile, Germany, Italy, Spain, Luxembourg and Belgium were still nowhere near meeting the pledge.
Spending in Bulgaria, the Baltics and the Netherlands went up by around 20% in 2018 compared to 2017.
Along with Canada, Greece was the only NATO members to decrease defence spending in 2018.
European nations as a whole reached a five-year high at 1.51%.
The US still accounts for nearly 70% of NATO’s military expenditures, which prompted Trump to question why the country was spending so much to protect "wealthy countries". He even threatened to withdraw from the alliance.
NATO's Secretary General Jens Stoltenberg responded to the report by complimenting the allies for “doing a lot more together", adding: "We must continue to stand strong together.”
“Standing with unity and resolve,” Stoltenberg said, “NATO will remain a pillar of stability for generations to come.”
Following the devastation of World War II, NATO, whose headquarters is in Brussels, was created to protect the people and territory of members in the Euro-Atlantic area against aggression from the Soviet Union.
The alliance was founded on the principle of collective defence, meaning that if one NATO country is attacked the others have to step in.