The prices of seats on major financial exchanges have plummeted dramatically in recent years. For example, at the Chicago Board of Trade, the world's biggest futures exchange, a membership seat sold for $$\$ 300,000$$ in 2012, down 65 percent from a record of $$\$ 858,000$$ in 1997 . Explain, using a graph, why the decline in the value of such seats may be related to the growth of electronic trading.