Year	gross (GPI)
1971	0.8194500207901
1972	0.990610003471375
1973	0.83050000667572
1977	0.934040009975433
1978	0.917810022830963
1983	0.975899994373322
1984	0.973630011081696
1987	0.942480027675629
1988	0.953819990158081
1990	0.915040016174316
1991	0.920360028743744
1992	0.976769983768463
1996	0.973860025405884
1998	0.81370997428894
1999	0.961009979248047
2002	0.946699976921082
2003	0.953610002994537
2004	0.962570011615753
2005	0.960810005664825
2007	0.989260017871857
2008	0.976189970970154
2009	1.00426995754242
2010	0.993319988250732
2011	0.970669984817505
2012	0.971099972724915
2013	0.979700028896332
2014	0.964569985866547
2015	0.961290001869202
2016	0.957469999790192
2017	0.967360019683838