There is also another kind of dollar index used by the Federal Reserve. It is called the “trade-weighted U.S. dollar index”.
The Fed wanted to create an index that could more accurately reflect the dollar’s value against foreign currencies based on how competitive U.S. goods are compared against other countries.
The main difference between the USDX and the trade-weighted dollar index is the basket of currencies used and their relative weights. The weights are based on annual trade data.
Currencies and Weights
Here is the current weighting of the index:
*Weights as of December 15, 2005
For more information on exchange rate indexes for the U.S. dollar, see "Indexes of the Foreign Exchange Value of the Dollar"
Weights for the broad index can be found at http://www.federalreserve.gov/releases/H10/Weights
If you’d like to see historical data, check out http://www.federalreserve.gov/releases/h10/Summary/