Nine teams that advanced to the round of 16 are from Europe along with four from Brazil and one each from Major League Soccer, Mexico and Saudi Arabia.
About 56.7 per cent of publicly listed capacity was filled for the 48 group stage matches, which included crowds of 3,412 and 6,730 in Orlando, Florida; 5,282 and 8,239 in Cincinnati.
FIFA did not provide specific capacities for the tournament despite repeated requests from The Associated Press.
Total announced attendance was 1.67 million from 2.95 million capacity, an average of 34,746.
Just 44.9 per cent was filled for five matches at MetLife Stadium in East Rutherford, New Jersey, the site of next year's World Cup final, and 50 per cent at the Rose Bowl in Pasadena, California, where the 1994 championship game was played.
Among other 2026 sites, 81.8 per cent of capacity was filled in Miami Gardens, Florida, 61.6 per cent in Philadelphia, 52 per cent in Seattle and 44.3 per cent in Atlanta.
FIFA spokesman Bryan Swanson did not respond to a request for FIFA President Gianni Infantino to discuss the tournament and attendance.
FIFA issued a statement that said: "The appetite of the tournament speaks for itself: fans from 168 countries have already purchased tickets ... a clear sign of global anticipation and reach."
The 12 games televised with English commentary on TNT, TBS and truTV averaged 360,000 viewers through Monday, including 409,000 for seven matches on nights and weekends.
The second round opens Saturday with an all-Brazilian matchup of Palmeiras and Botafogo, followed by Chelsea-Benfica later in the day.
Sunday starts with the high-profile meeting of Inter Miami and Lionel Messi against European champions Paris Saint-Germain and is followed by Bayern Munich-Flamengo.
Inter Milan-Fluminese and Manchester City-Al Hilal are on Monday, and Real Madrid-Juventus and Borussia Dortmund-Monterrey on Tuesday.
European teams won 16 of the 17 previous editions of an eight-team Club World Cup, the lone exception a 2012 victory by Brazil's Corinthians over Chelsea.
Five of the 12 stadiums being used are sites for next year's World Cup, which will have 104 matches instead of 64 and many more games lacking prestigious teams and players.
There were five weather delays in the Club World Cup group stage and temperatures at times rose well over 90 degrees (32 Celsius), a sign that climate change could impact next year's World Cup. However, four of the stadiums for next year's tournament have roofs and climate control.
11°C