Because of their higher efficacy, CFLs use between one-seventh and one-third of the power of equivalent incandescent lamps. Fifty to seventy percent of the world's total lighting market sales were incandescent in 2010. Replacing all inefficient lighting with CFLs would save per year, 2.5% of the world's electricity consumption. In the US, it is estimated that replacing all the incandescents would save 80 TWh yearly. Since CFLs use much less energy than incandescent lamps (ILs), a phase-out of ILs would result in less carbon dioxide () being emitted into the atmosphere. Exchanging ILs for efficient CFLs on a global scale would achieve annual reductions of 230 Mt (million tons), more than the combined yearly emissions of the Netherlands and Portugal.