The video game industry involves the development, marketing, and sale of video games. It employs thousands worldwide in dozens of job disciplines and is a multi-billion dollar annual industry. While initially a niche market in the 1970s, the computer and video game industries have grown significantly. As games have evolved, the development process and job roles have become more complex. Major game companies operate worldwide, including companies like Overflow in Japan, Accolade in the US, and Adventure Soft in the UK. These companies may have additional media interests and ownership from other companies. The game industry is also linked to other industries like film, through movie tie-in games, and music, through soundtracks.