To no one’s surprise, World of Warcraft earned more revenue than any other subscription-based MMO in the world during 2013, according to a new report from SuperData Research. What may come as a surprise is the fact that Star Wars: The Old Republic came in at number four on the list.

The BioWare-developed Star Wars MMO brought in $165 million in worldwide revenue in 2013, SuperData reports. That’s a far cry from the $1.041 billion in revenue earned by WoW during the same period, but it’s a figure only topped by Lineage ($253 million, despite its North American servers shutting down years ago–it originally launched in 1998) and TERA ($236 million).

For the purposes of the report, “pay-to-play” MMOs are considered any games “that earn revenue from subscriptions, expansion packs, and microtransactions-based virtual items and services (e.g. experience boosts, items, mounts, and server transfer fees).”

That’s a market that has been “shrinking since 2010,” as can be seen in the graph below. In 2010, there were 30.6 million active monthly subscribers worldwide, a figure which dropped to 23.4 million in 2013. This has resulted in a move toward relying increasingly on microtransactions, if not outright adopting a free-to-play model that is entirely dependent on them.

That’s the case with The Old Republic, which offers a subscription option but is otherwise microtransaction-based. This has been the case since November 2012, when the game switched to a free-to-play model after it struggled to keep hold of subscribers as a subscription-only game. EA said last May that the game’s revenue doubled following the move.

The percentage of revenue that MMOs earn from microtransactions has gone up from 14 percent to 27 percent in the last five years, the report continues. (The graph above shows how that coincides with a drop in subscription revenue.) The average digital spend has also increased worldwide during that span, going from $16 to $46.

We’ve seen a pair of high-profile subscription-based MMO launches this year in The Elder Scrolls Online (April) and WildStar (June). As WildStar provides buyers of the game with a free month of subscription time, it’s not yet clear how much of its audience it will be able to retain. Traditionally, subscription-based MMOs lose a portion of their user base after the initial month when people decide not to renew their subscriptions. ESO, though, has held on to 772,374 of its subscribers as of June, according to SuperData. As always when evaluating MMOs, this may look poor when held up to WoW’s most recent subscription numbers–7.6 million as of March 31–but it’s actually a strong number.

Do you still play any MMOs, or have you moved on from the genre like I have? Let us know in the comments.

Chris Pereira is a freelance writer for GameSpot, and you can follow him on Twitter @TheSmokingManX
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