There are now more than 700 hyperscale data centers around the world.

That’s twice as many as existed just five years ago, according to a study released last week by Synergy Research Group. At the same time, the computing power contained within those data centers has grown even faster, doubling in just four years. The global data center inventory reflects the accelerating pace of digital transformation and its direct impact on commercial real estate — trends that Synergy Chief Analyst John Dinsdale said he doesn’t see slowing down any time soon.

“The constants in all of this are that both the number and average size of hyperscale data centers continue to grow steadily,” Dinsdale said.  “We also see a very healthy pipeline of hyperscale data centers being planned, developed or fitted out, supporting strong five-year growth forecasts.”

Synergy’s numbers — based on an analysis of the data center footprints of 19 of the world’s largest cloud and internet service firms — provide context as to who is driving the rapid pace of data center development around the world. Cloud providers Amazon, Microsoft, Google and IBM have the most data centers, each with more than 60 facilities scattered globally.

Amazon, Google and Microsoft also have the largest footprint measured by computing capacity, with Facebook close behind. Properties operated by Oracle, Alibaba and Tencent also make up a significant percentage of the global inventory.

Dinsdale said that while the total number of data centers is interesting, the overall capacity is more important in terms of understanding the global data center development market.

“Not all data centers are born equal,” Dinsdale said. “Generally speaking, self-owned data centers are much bigger than leased data centers and data centers in the home country of a hyperscale company are much bigger than its international facilities, though there are plenty of exceptions to these trends.”

Although international data center markets continue to gain steam, the U.S. continues to control the bulk of data processing and storage, according to the study. Indeed, any shift away from the U.S. as the center of digital infrastructure is happening slowly.

The U.S. is responsible for 49% of the world’s IT capacity, according to Synergy, and is losing market share at a rate of just 1% annually. China, the nation with the second-largest inventory, only controls 15% of the world’s capacity. Analysts expect this number to grow, as Chinese firms ByteDance, Alibaba and Tencent have the industry’s fastest-growing data center footprints, according to the report.