Year	gross (GPI)
1971	0.374989986419678
1973	0.482360005378723
1974	0.449479997158051
1975	0.381469994783401
1976	0.365079998970032
1982	0.617999970912933
1983	0.628840029239655
1984	0.599319994449615
1985	0.605599999427795
1986	0.652310013771057
1987	0.715040028095245
1988	0.728120028972626
1989	0.702250003814697
1992	0.669250011444092
1993	0.763329982757568
1994	0.74057000875473
1995	0.691309988498688
1996	0.730840027332306
1997	0.711499989032745
1999	0.724979996681213
2000	0.659860014915466
2001	0.626110017299652
2002	0.620609998703003
2004	0.685180008411407
2005	0.66211998462677
2006	0.676789999008179
2007	0.721449971199036
2008	0.742500007152557
2009	0.8089399933815
2011	0.936500012874603
2012	0.905610024929047
2013	0.905830025672913
2014	0.95430999994278
2015	0.945129990577698
2016	0.966520011425018
2017	0.990400016307831
2018	1.00260996818542
2019	1.03419995307922
2020	1.03258001804352
2021	1.01098001003265