(click on chart to enlarge)
The US Dollar has now been displaced by the Euro according to the value of cash currency in circulation world wide. There is more Euro cash being used in the world than there is USD cash being used by the world.
And, the US Dollar has now been displace by the Euro for the currency of the majority of the world's bond markets (the denomination of the debt instruments). The total value of Euro denominated debt is larger than the total value of USD denominted debt.
The Euro has done this in only about 6 years.
That's to say nothing about oil in some countries starting to be denominated in Euros as well as being paid for in Euros, or taken in trade for other goods.
The US Dollar was down near the 80 level for the first time in 1978. It has been down there 4 more times since. The more the 80 level gets probed, the weaker this level becomes as support.