Green building remains red hot despite a sluggish economy that has curtailed new development, New York-based McGraw-Hill Construction reported. Green construction grew 50 percent during the last two years from $42 billion up to $71 billion, the report said. It will account for about 25 percent of all new building activity in 2010, the report added.McGraw-Hill Construction projected market spending for green building will reach $135 billion by 2015. A third of all new nonresidential construction