States dropped to $1.33 billion in 1999, and reached a low of $866 million in 2004. Furthermore, by the early 2000s, networked gaming via computers and then consoles across the Internet had also appeared, replacing the venue of head-to-head competition and social atmosphere once provided solely by arcades. Cross-platform Game engines originating in the very late-1990s, became extremely popular in the 2000s, as they allowed development for indie games for digital distribution. Noteworthy software include GameMaker and Unity. Well-known indie games made in that decade include I Wanna Be the Guy, Spelunky, Braid, Clean Asia!, Castle Crashers, World of Goo, Dino Run, The Impossible Game and Alien Hominid. Worldwide, arcade game revenues gradually increased from $1.8 billion in 1998 to $3.2 billion in 2002, rivalling PC game sales of $3.2 billion that same year. In particular, arcade video games are a thriving industry in China, where arcades are widespread across the country. The US market has also experienced a slight resurgence, with the number of video game arcades across the nation increasing from 2,500 in 2003 to 3,500 in 2008, though this is significantly less than the 10,000 arcades in the early 1980s. As of 2009, a successful arcade game usually sells around 4000 to 6000 units worldwide. Sega Corporation, usually styled as SEGA, is a Japanese multinational video game software developer and an arcade software and hardware development company headquartered in Japan, with various offices around the world. Sega previously developed and manufactured its own brand of home video game consoles from 1983 to 2001, but a restructure was announced on January 31, 2001, that ceased continued production of its existing home console (Dreamcast), effectively exiting the company from the home console business. In spite of that, SEGA would go on to produce several videogames such as Super Monkey Ball franchise, the Sega Ages 2500 PlayStation 2 games, Hatsune Miku: Project DIVA, Sonic Adventure 2, Sonic Heroes, Rez, Shadow the Hedgehog, Virtua Fighter 4, After Burner Climax, Valkyria Chronicles, Sonic Pinball Party, Bayonetta, Jet Set Radio, Puyo Pop Fever, Thunder Force VI, Shenmue II, Phantasy Star Online, Yakuza 2, Gunstar Super Heroes, Astro Boy: Omega Factor, OutRun 2006: Coast 2 Coast and Mario & Sonic at the Olympic Games. Neo Geo is a family of video game hardware developed by SNK. The brand originated in 1990 with the release of an arcade system, the Neo Geo MVS and its