No one doubts that the video game industry sees enormous annual growth as games become more ubiquitous in our daily lives on our mobile phones, televisions, and computers.

But did you know that this growth in the game industry is also reflected in Forbes' annual billionaires list? The magazine's famous list includes some people who derive their wealth from video games, either directly through the development of highly successful games or indirectly by providing a platform for them. Here are six of the most notable video game billionaires:

Bill Gates - 86.2 Billion Dollars

The world's richest person derives around 13% of his total wealth from Microsoft, the software giant he founded in 1975.

Although the company made its name by creating operating systems and business software, it is also one of the world's largest video game companies thanks to Xbox. In its latest financial quarter, the company earned more than US$3 billion from games, around 14% of its total revenue.

And since we are talking about Microsoft, Steve Ballmer also deserves an honorable mention. The former company president saved Xbox from bankruptcy and, according to research by the Betway Casino website, took eight years to go from millionaire to billionaire.

William Ding - 17.3 Billion Dollars

The founder of internet giant NetEase was also China's first gaming billionaire. In addition to domestic titles, the company partners with Activision Blizzard on World of Warcraft and Hearthstone in China and holds the exclusive license for Minecraft. Ding's net worth has risen by more than US$2 billion since 2016.

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CrossFire

Kown Hyuk-Bin - 4.9 Billion Dollars

In the 15 years since Kown Hyuk-Bin founded Smilegate, it has become one of South Korea's largest game companies. CrossFire is the world's most popular first-person shooter, remaining strong almost a decade after its release. The company's sales in 2016 totaled US$572 million—more than 10% above 2015.

Gabe Newell - 4.1 Billion Dollars

Gabe Newell leads Valve Corporation, creator of some of the most iconic franchises in recent U.S. gaming history, including Half-Life, Portal, and Left for Dead.

It is also one of the largest distributors of PC games thanks to its Steam platform. The company is also at the forefront of several gaming fields, including virtual reality, thanks to its partnership with HTC in creating the Vive, a VR headset.

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Gabe Newell

Kim Taek-Jin - 1.2 Billion Dollars

Kim Taek-Jin is the founder and CEO of NCSOFT, one of South Korea's largest game publishers. The company focuses on online multiplayer RPGs such as Guild Wars and Blade & Soul, played in more than 60 countries. Due in part to expanding its titles to mobile devices, it saw a US$880 million increase in revenue.

Kagemasa Kozuki - 1.1 Billion Dollars

Kagemasa Kozuki, founder and chairman of Japanese video game giant Konami, did not set out to make his fortune from video games. When he founded Konami in 1969, it was a jukebox repair and rental company.

In the late 1970s, however, Kozuki moved his company into the emerging video game industry, manufacturing arcade games. During the 1980s, the company began publishing games for the Nintendo Entertainment System, and the business took off—producing franchises such as Castlevania, Contra, Metal Gear, and many more. The company remains strong today—its shares rose by more than 60% over the past, and its revenue totaled almost US$1.5 billion one year ago.