[flaque]

That is one crap graph. What’s the Y axis?

[iamdave]

I'm going to guess using the context clue of the title of the graph that it's the average cost of a house in thousands?

[jgraham]

Pretty sure it must be percentage of the 1997 value, otherwise it's hard to understand how the scale can accomodate both house prices and population in a single set of units.