 Yeah. The thing that we have to realize is that the production of Portland cement has been around for at least 150 years. Right. And the reality is, is the production of commodity chemicals, the production method tends to change every 50 or 100 years. It takes a long time. The global economy really has to change in order to make a new system more economical. Right. So for over a century, limestone was the most economical way to make cement.