Charts data specialists Enterbrain, NPD and Gfk Chart-Track have announced a worldwide partnership.

The companies, which individually specialise in sales data from Japan, the US and the UK, will report global sales based on point-of-sale data in the monthly Top Global Markets Report.

"The video games business has become increasingly global, with the majority of the publishers releasing games in multiple markets," commented Anita Frazier, industry analyst for The NPD Group.

"The US as the world's largest market will be able to view and compare sales for the first time outside of their own market."

Users will be able to track titles, unit sales and share, as well as dollar sales and revenue share in the three regions.

"This partnership represents a great opportunity to benefit not only our clients but the industry as a whole by providing a comprehensive, industry-supported view of sales across the three largest video game markets," offered John Pinder, MD of GfK Chart-Track.

The first Top Global Markets Report reveals that Grand Theft Auto IV is the biggest seller this year to date, with a total 6,293,000 units sold despite only being released in two of the three monitored regions.

Super Smash Bros. Brawl has sold 5,433,000 units, Mario Kart Wii 4,697,000 units and Wii Fit 3,604,000 units in the three regions combined.

The fifth biggest seller this year is Guitar Hero III: Legends of Rock with 3,475,000 units.