Oceaneering International, Inc. is a global provider of engineered services and products, primarily to the offshore oil and gas industry. Oceaneering also serves the offshore renewables, defense, aerospace and commercial theme park industries. Oceaneering was organized as a Delaware corporation in 1969 out of the combination of three diving service companies founded in the early 1960s. Since our establishment, we have concentrated on the development and marketing of underwater services and products to meet customer needs requiring the use of advanced technology. We believe we are one of the world's largest underwater services contractors. The services and products we provide to the energy industry include remotely operated vehicles, specialty subsea hardware, engineering and project management, subsea intervention services, including manned diving, survey and positioning services, seabed preparation and asset integrity and nondestructive testing services. Our foreign operations, principally in the North Sea, Africa, Brazil, Australia and Asia, accounted for approximately 50% of our revenue, or $1.0 billion, for the year ended December 31, 2018.
Our business segments are contained within two businesses - services and products provided primarily to the oil and gas industry, and to a lesser extent, the offshore renewables industry ("Energy Services and Products") and services and products provided to non-energy industries ("Advanced Technologies"). Our four business segments within the Energy Services and Products business are Remotely Operated Vehicles ("ROVs"), Subsea Products, Subsea Projects and Asset Integrity. We report our Advanced Technologies business as one segment. Unallocated Expenses are expenses not associated with a specific business segment. These consist of expenses related to our incentive and deferred compensation plans, including restricted stock and bonuses, as well as other general expenses.
Energy Services and Products. The primary focus of our Energy Services and Products business over the last several years has been toward increasing our asset base and capabilities for providing services and products for offshore operations and subsea completions. In recent years, we have focused on increasing our service and product offerings toward our oil and gas customers' operating expenses and the offshore renewable energy market.