Jack... from the late 1970's up until 1986 the prices of stamps
skyrocketed to levels not even seen today... sparked by stamps
being (formerly) classified as a portfolio investment, which was
eliminated in the tax revision, and, hence, the stamp market had
collapsed...
I'm really not certain what year anyone could say it began making
a strong comeback, but most certainly after 1995, where
ebay became
the major focal point for many buyers and sellers...
I recall, though, between 1987 and 1992-1994, where you could walk
into a stamp shop and just about name your own price on just about
anything which caught your eye...