"Global investment in renewable power and fuels increased 17% to a new record of $257 billion in 2011. This was more than six times the figure for 2004, and 94% more than the total in 2007, the last year before the acute phase of the world financial crisis. Wind is the most mature of the “new” renewable power technologies, and has usually been the biggest single sector for investment over recent years. However in 2011, it was out-stripped by solar, which attracted nearly twice as much investment." (Quoted from paper)