Answer
The trendline is on the graph, and the equation is $y=5.4333x-10558$
The estimated attendance is 335.766 million people.
Work Step by Step
The graph was made in Microsoft Excel.
$y=5.4333*x-10558$
$y=5.4333*2005 - 10558$
$y=10893.766 - 10558$
$y = 335.766$