A reconciliation of any non-GAAP financial measures not reconciled in these comments to the most comparable GAAP financial measure can be found in our earnings press release, slides, or companion documents. Today, I'll be reviewing our first quarter results as well as providing my outlook for the markets we serve. Backlog at quarter-end was $20.3 billion, a $1.4 billion sequential increase and a new record level. Revenue, EBITDA, and EPS were all above guidance with strong year-over-year double-digit growth.
EBITDA margins improved 170 basis points versus last year first quarter, and total company book-to-bill was 1.4x, setting yet another backlog record. The fundamentals continue to improve, driven by strong growth in total data usage. This growth is fueled by increasing demand for streaming video, cloud computing, gaming, and connected devices. The rapid expansion in total network traffic underscores durable demand and significant long-term growth potential.
AI is driving a level of demand for fiber capacity, redundancy, and low latency that we haven't seen before. A big part of that demand is coming from AI and data centers, which could drive up to 12% of total U.S. That kind of growth requires significant expansion of the grid, new transmission lines, substations, and upgrades across the system. When you combine load growth, resilience, and energy transition, it creates a long duration, highly visible opportunity set, and we think we're really well positioned there.