The rate of productivity growth and the development, or what I call new ideas, has been slowly declining. The amount we're spending on science, R&D professionals, and money by firms by the government has actually been rising. So it looks like it's getting harder and harder to come up with new ideas. But given there's only been two changes over the last 200 years in rate of progress, I think it's reasonably safe to say. We're making steady, slow, reasonable productivity growth. It's not zero, but it's certainly harder.