Of our U.S. government revenue, fixed-price contracts accounted for 59% in 2020 and 2019 and 56% in 2018; cost- reimbursement contracts accounted for 35% in 2020 and 2019 and 38% in 2018; and time-and-materials contracts accounted for 6% in 2020, 2019 and 2018. For information on the advantages and disadvantages of each of these contract types, see Note B to the Consolidated Financial Statements in Item 8. Our U.S. commercial revenue was $4.9 billion in 2020, $6 billion in 2019 and $4.8 billion in 2018, which represented 13%, 15% and 13% of our consolidated revenue in each of the respective years. The majority of this revenue was for business jet aircraft and related services where our customer base consists of individuals and public and privately held companies across a wide range of industries. Our revenue from non-U.S. government and commercial customers was $6.7 billion in 2020, $7.6 billion in 2019 and $7.8 billion in 2018, which represented 18%, 19% and 22% of our consolidated revenue in each of the respective years. We conduct business with customers around the world. Our non-U.S. defense subsidiaries maintain long-term relationships with their customers and have established themselves as principal regional suppliers and employers, providing a broad portfolio of products and services. Our non-U.S. commercial revenue consists primarily of business jet aircraft exports and worldwide aircraft services. While the installed base of aircraft is concentrated in North America, orders from customers outside North America represent a significant portion of our aircraft business with approximately 60% of the Aerospace segment’s aircraft backlog on December 31, 2020. Several factors determine our ability to compete successfully in the defense and business-aviation markets. While customers’ evaluation criteria vary, the principal competitive elements include: The U.S. government contracts with numerous domestic and non-U.S. companies for products and services. We compete against other contractors as well as smaller companies that specialize in a particular technology or capability. Outside the United States, we compete with global defense contractors’ exports and the offerings of private and state-owned defense manufacturers. Our Marine Systems segment has one primary competitor with which it also partners on the Virginia-class and Columbia-class submarine programs. Our Combat Systems segment competes with a large number of U.S. and non-U.S. businesses. Our Technologies segment competes with many companies, from large 14 DEFENSE MARKET COMPETITION COMPETITION NON-U.S. U.S. COMMERCIAL • the technical excellence, reliability, safety and cost competitiveness of our products and services; • our ability to innovate and develop new products and technologies that improve mission performance and adapt to dynamic threats; • successful program execution and on-time delivery of complex, integrated systems; • our global footprint and accessibility to customers; • the reputation and customer confidence derived from past performance; and • the successful management of customer relationships.