Denominated in what?
It is flawed to convert dollars from one year into 1998 dollars. On what basis is this done? Is it done in an accurate manner in which the total money supply is considered? Or is it based on some inflation number based on some arbitrary index?
You need to look at the actual number. How many paper dollars did an ounce of gold fetch in a particular year? One ounce of gold is one ounce of gold. It is dollar that changes in value and no attempt should be made to even out its value over the years.