300 -- the percent by which real estate and construction professionals overestimate the costs of green building, according to a study by the World Business Council for Sustainable Development. [pdf]
5 -- the actual cost premium, in as a percentage, for green building. Further...
19 -- the percent of greenhouse gases emitted by buildings, according to survey respondents.
40 -- the actual percent of greenhouse gases emitted by buildings.
That's right: industry folks overestimate the costs of going green(er) and underestimate the damage being done. As Dave at Gristmill notes, all we need is some proper education to turn it around. ::World Business Council for Sustainable Development via ::Gristmill