Year	gross (GPI)
1971	0.832629978656769
1975	0.849489986896515
1976	0.853169977664948
1977	0.89121001958847
1980	0.988940000534058
1981	0.913540005683899
1983	0.925100028514862
1984	0.917699992656708
1986	0.929059982299805
1988	0.955789983272552
1989	0.950919985771179
1991	0.964699983596802
1992	0.9721400141716
1993	0.984669983386993
1994	0.981029987335205
1995	0.971849977970123
1996	0.971000015735626
1998	1.01855003833771
1999	1.05885004997253
2000	1.07493996620178
2001	1.06579995155334
2002	1.06122994422913
2003	1.06596994400024
2004	1.02586996555328
2005	1.01452994346619
2006	1.0207200050354
2007	1.04910004138947
2008	1.0293300151825
2009	1.02869999408722
2010	1.01619005203247
2011	1.00622999668121
2012	0.993499994277954
2013	1.03961002826691
2014	1.03503000736237
2015	1.00803005695343
2016	1.00183999538422
2017	0.989719986915588
2018	0.989440023899078
2019	0.970679998397827
2020	0.962339997291565