Hi Tomer!
Glad you brought that up.
I also wonder how many copies an adventure game usually sells, including downloads.
I don't think anyone would release an adventure game if it only sold 11k worldwide, or only 500 copies in America in a week.
If you look at the bottom of the page, it says "Figures in the above tables are millions of units sold."
If so, that should mean that Gray Matter has sold 11 million copies worldwide, and that sounds more right to me