Square Enix have revealed lifetime sales data for major Eidos franchises as well as their own major franchises. The biggest highlight is that the Tomb Raider series has sold over 30 Million copies in total. The first game in the series sold the most, selling almost 8 million copies, since then however the sales for each successive game has steadily decreased, with slight resurgences over time.
The Hitman series is reported to have sold approximately 8.3 million units, with Hitman 2 selling nearly 4 million of those, and the Deus Ex series has sold about 2.4 million units, with the second game in the series selling slightly more than the original.
Kane & Lynch still managed to sell 1.7 Million copies, despite all the bad press it initially received. Click the images below for full size:
Source: http://www.ps3center.net//news/2804/lifetime-sales-of-eidos-franchises-revealed/
Tomb Raider is still doing alright, but 8million to 2million is still a large difference.
