Amazon has spent nearly $13.9 billion in a huge three-year push to expand its warehouse facilities, Bloomberg reports. According to data compiled from the last several years, the company has built 50 new facilities since 2010 for a total of 89, with five more announced for this year. It's also cut down dramatically on construction time, building and staffing a warehouse in eight to twelve months rather than the two years it took before the spending boost. And Amazon iterates quickly on each design, says worldwide operations and customer service vice president Dave Clark. "Every time we open a building, we take the lessons learned, we redo the design and open the next year's." New warehouses can pack around twice as much inventory as those built four or five years ago, he says.

The increase in spending — about 40 percent a year from 2010 to 2013, compared to 24 percent in 2009 — is squeezing Amazon's finances, but it's growing for good reason. In addition to competing with brick and mortar stores, Amazon is now fending off companies like Google and eBay, which have shown interest in super-fast shipping, as well as smaller delivery startups. There's also, however, an ongoing push and pull between the company's desire to grow and its vulnerability to sales taxes, which it's gone to great lengths to avoid. Having a physical presence in a state may let it deliver goods faster, but it also gives local governments an excellent case for collecting some extra revenue.