There is also continual improvement in technology. You may have seen in the rural parts of the country places where the panels actually move with the sun, so that they get the maximum expression of the panel surface to the sun. On the actual panel itself, we're now seeing that micro-reflectors can concentrate the sun's rays before they actually hit the panel surface, in a way that improves the performance. So the technological improvement that is going on in solar panels is also adding to the cost factor that John is talking about in terms of which panel you're using and under what circumstances.
On October 2nd, 2012. See this statement in context.