It's both to natural gas and renewable energy projects. Solar and wind projects in the U.S. have been growing very quickly. For example, in California we get between probably 30% and 35% of our energy from renewables, such as solar, wind, geothermal and some other things like biomass and others, and, of course, in some parts of the U.S., large hydro projects are very common. We're also seeing, with regard to transportation-related emissions that cars are getting more efficient, although a lot depends on the price of gasoline. We're seeing more and more electric and diesel hybrid vehicles on the road.
I think those are the primary reasons.