Association football is the world's most popular sport, and is worth US$600 billion worldwide. By the end of the 20th century it was played by over 250 million players in over 200 countries. Around the world, the sport is played at a professional level by professional footballers, and millions of people regularly go to football stadiums to follow their favourite football teams, while billions more watch the sport on television or on the internet. Football has the highest global television audience in sport. The sport had amateur origins and evolved into the modern professional competition.