The vast majority of $100 bills are abroad, not in the United States. So yes, of course there's a use here but nowhere near as much as there's a use for $100 bills abroad.

The worst loophole is what Donald Trump has talked about: the tax deductibility of interest. If you let real estate owners or corporate raiders borrow the money to buy a property or company, and then pay interest to the bondholders, you'll load the company you take over with debt. But you don't have to pay taxes on the profits that you pay out in this way. You can deduct the interest from your tax liability.

If you increase living standards, you make labor more productive. This is why Asia today is becoming more productive than the United States.

Oil is a special case. Saudi Arabia is trying to drive U.S. fracking rivals out of business, while also hurting Russia. This lowers gas prices for U.S. and Eurozone consumers, but not by enough to spur economic recovery.

Trump has said that he wants to remove the tax deductibility of interest. If he can do that, fine. But I hope that Trump knows that it's not the President that sets tax policy. It's Congress.

If you look at payments to labor as a proportion of national income or gross domestic product, you find profits going way up, investment and savings going up.

Governments create money and spend it into the economy by running budget deficits. The paper currency in your pocket is technically a government debt.