How many individual countries participate in G20 summit ?

The G20 comprises 19 individual countries plus the European Union. The 19 countries are: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, UK, and USA. The EU is the 20th member but is a political-economic union, not an individual country. Therefore, '19' is the correct answer for individual countries.