“Above $100 indicates USD strength - Below $100 indicates USD weakness “
Not quite. 100 was set in 1973 when the index was started.
If it was started at another time, the current value could be 125 or 80.
Your make a valid point.
However, very few Free Republic readers have traded currency futures, so I am making a helpful, but general, comment that adds some meaning to the numbers.
Regardless, the peaks and valleys of the 1973 chart definitely correspond with professional commentary about a strong or weak USD.