Yes, the investment of $3.6 billion is over five years. It started in late 2014. It's to support all of our infrastructure work to natural and cultural areas, so not just national historic sites. We estimate that approximately $1.3 billion is being invested to preserve, rehabilitate, and restore national historic sites. Again, those can be structures, not necessarily all the cultural resources in those sites but the broad national historic sites. It could be all kinds of repair.
As I mentioned in my remarks, there was a lot of deferred maintenance over the years on a lot of our assets, so this is really aimed at this. As we are doing this work, we are doing impact assessment on cultural resources and making sure the work is done in a way to protect and preserve our cultural resources.