Updated

President Donald Trump is scheduled to attend the Group of 20 (G-20) summit this week.

Heads of state and government are expected to attend the event in Hamburg, Germany, on July 7 and July 8. Here's what you should know about the international forum.

Who's in the G-20? 

Nineteen countries and the European Union. The United States is in the group, as are Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, and the United Kingdom.

Together, they "account for more than four-fifths of gross world product and three-quarters of global trade, and are home to almost two-thirds of the world's population," according to the G-20 website. Germany is currently in charge of the G-20 presidency, which changes each year. Whoever hosts the summit can establish its agenda and guide talks, according to The Telegraph.

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Who else is invited this year? 

Norway, the Netherlands, Singapore, the African Union (AU), the Asia-Pacific Economic Cooperation (APEC) and the New Partnership for Africa's Development (NEPAD) were invited by Germany. Spain is a permanent guest invitee.

What does the G-20 focus on? 

World leaders "traditionally focus on issues concerning global economic growth, international trade and financial market regulation," according to the site. Summit outcomes are described in published declarations. As part of the declaration from the 2016 G-20 Summit, leaders said they would "pursue innovative growth concepts and policies" and would "work harder to build an open world economy."

How did the G-20 develop? 

The initial G-20 meeting grew out of the G-7, which is a group of industrial democracies consisting of France, Germany, Italy, Japan, the United Kingdom and the United States. The 1999 meeting of finance ministers and central bank governors occurred as a reaction to a financial crisis in Asia.

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"In the dramatic early days of the financial crisis in 2008, it quickly became apparent that the necessary crisis coordination would only be possible at the highest political level," the G-20 website says, explaining that the finance ministers and central bank governors meetings "were raised to the level of heads of state and government."

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The G-20 Leaders Summit, however, occurred for the first time in Washington, D.C., in 2008, "amid serious challenges to the world economy and financial markets," a meeting declaration said. There were two G-20 Summits in 2009, two in 2010, and annual summits from 2011 to 2016. 

G-20 finance ministers and central bank governors meetings have taken place during the years. Treasury Secretary Steve Mnuchin was among the attendees at one such meeting in Baden-Baden, Germany, in March.