The personal computer (PC) gaming industry dates back to the late 1970s, but really began to boom in the 1990s. In 2005, consumers spent $1.4 billion on video games for PCs in 2005, according to research released by analysts NPD Group. Of that, $344 million came from subscriptions to online games and gaming Web sites, according to NPD's estimate. This number has since increased along with the generally growing video game market and with the release of popular PC games such as World of Warcraft and The Sims. The worldwide PC-based game market is worth as much as $10.7 billion as of 2008. This number includes retail sales, online revenue, digital distribution and relevant ad sales.
According to Forbes , A many years the PC has become the most lucrative market in the industry, thanks to its unique hardware performance and characteristics. In consequence of this, the PC receives a average 300 new monthly releases, 90% of them is Exclusive titles, while other platforms receive 10-30 Title month to month and Exclusive titles just represent 10% on these platform.
The largest PC gaming markets:
It's important to keep in mind, however, that this NPD data concerns retail data only and does not include sales of digitally downloaded games, micro-transactions, online subscriptions (e.g. World of Warcraft), etc. The NPD Group recently started paying more attention to online revenue, but this data does not include that.