Improving energy efficiency is a shared policy goal of many governments around the world. The benefits of more efficient use of energy are well known. Not only does it reduce energy costs and investments in energy infrastructure, it also lowers fossil fuel dependency and CO2 emissions, while at the same time increasing competitiveness and improving consumer welfare. Yet many questions remain unanswered. What are the latest trends in global energy use and CO2 emissions? How do factors such as demography, economic structure, income, lifestyle and climate affect these trends? Where are the greatest potentials to further improve energy efficiency, and which data are required to support energy efficiency policy development? This publication answers these questions using the latest insights from the IEA energy indicators work. The goal is to show policy makers how in-depth indicators can be used to track the progress in efficiency and identify new opportunities for improvements.