The 2014 Russian annexation of Crimea led to strong condemnation by NATO nations, and Poland invoked Article 4 in meetings. Then, at the 2014 Wales summit, the leaders of NATO's member states formally committed for the first time spend the equivalent of at least 2% of their gross domestic product on defence by 2024, which was previously only an informal guideline. In 2015, five of its 28 members met that goal. At the beginning of 2018, eight members either were meeting the target or were close to it; six others had laid out plans to reach the target by 2024 as promised; and Norway and Denmark had unveiled plans to substantially boost defense spending, including Norway's planned purchase 52 new F-35 fighter jets.