Inflation isn't the only thing that affects the value of USD. UDS's perceived value fluctuates with regard to investors' value perceptions of other currencies,

Inflation isn't the only thing that affects the value of USD. UDS's perceived value fluctuates with regard to investors' value perceptions of other currencies, commodities, etc. Edit: If you think that USD has a fixed value, you are mistaken. You may use it as your reference point, but that just makes you blind to the fact that the perceived values of all currencies and assets are fluctuating all the time. There are some which are more closely tied together, and some which are less.