Year	gross (GPI)
1976	0.922879993915558
1978	0.924769997596741
1979	0.929279983043671
1980	0.919539988040924
1981	0.915809988975525
1982	0.927450001239777
1983	0.953499972820282
1984	0.945689976215363
1985	0.935949981212616
1986	0.936429977416992
1987	0.940090000629425
1988	0.954760015010834
1989	0.954240024089813
1990	0.946529984474182
1991	0.949710011482239
1992	1.01279997825623
1993	1.04384994506836
1994	1.00525999069214
1995	0.981710016727448
1996	0.986419975757599
1997	0.969780027866364
1999	0.968180000782013
2000	0.976209998130798
2001	0.987320005893707
2004	0.980199992656708
2005	0.978039979934692
2006	0.985040009021759
2007	0.99686998128891
2008	0.999790012836456
2009	1.01780998706818
2010	1.00568997859955
2011	1.00029003620148
2012	0.990100026130676
2013	0.98158997297287
2014	0.976679980754852
2015	0.982420027256012
2016	0.993550002574921
2017	1.00432002544403
2018	1.01730000972748
2019	1.018630027771
2020	1.02399003505707
2021	1.02570998668671