There's a big difference between having other countries use our currency, and having a currency union like the European Union -- and I presume that is what this poll is based on, since that would make the dollar analogous to the euro. The fact is, the EU periphery is in shambles. Their central bank doesn't have an employment mandate, and even if it did, adjusting interest rates would screw over some countries at the expense of others -- e.G., Germany is doing well, and thus they would vote against monetary stimulus, while Greece is doing horrible, and could benefit from rate cuts. The whole thing is a giant bloody mess, and we know from history that countries with debts nominally denominated in their own countries have no problem borrowing. If you care at all about debt or currency stability, a currency union is a horrible, failed experiment.