As part of Polyphony Digital's periodic update on its official sales site, the studio revealed the latest sales uptake since the last update. According to the latest figures It appears that Gran Turismo 5 has sold a whopping 1.7 million more copies since last December.
While Gran Turismo 5 was released near the end of 2010, the game seems to continue to sell impressively to this day as the sales of the game recently crossed 9 million units. To put things into perspective, GT5 has sold fairly close to what Forza 4 (a 2011 release) sold during the same time period (December 2011 - September 2012). Forza 4 is estimated to have sold a little over 2 million during the 10 month period of its release 12 months ago.
Total franchise numbers for Gran Turismo now top 67.8 million units as of September. With sales for Gran Turismo 5 surpassing 9 million units, the single iteration is now closing in on the lifetime sales of the entire Forza franchise which is estimated to be at 12 million which includes Forza Motorsport (original Xbox), Forza 2, Forza 3 and Forza 4.
Current gen cycle releases for Polyphony Digital also include Gran Turismo 5 Prologue, which sold 5.35 million units and Gran Turismo PSP, which sold 3.86 million units bringing the sales total for all three games to 18.20 million units over the past six years.
Polyphony Digital has been praised for continuously bringing substantial updates to their games far beyond the release date. One of the most recent updates was the massive Spec 2.0 DLC, which was offered for free that brought a ton of new content to the game.
The studio also has a pretty good race car program where the best GT video game players are flown to GT Academy to duke it out for the opportunity to become a professional race car driver. Kazunori Yamauchi, head of Polyphony Digital recently confirmed that the studio is working on Gran Turismo 6 but refused to reveal the timing of the release.