Year	gross (GPI)
1975	0.856679975986481
1976	0.875710010528564
1977	0.877860009670258
1978	0.878660023212433
1979	0.87923002243042
1980	0.877110004425049
1981	0.867150008678436
1982	0.861450016498566
1983	0.862550020217896
1984	0.867009997367859
1985	0.862789988517761
1986	0.886910021305084
1987	0.897520005702972
1988	0.903840005397797
1989	0.911719977855682
1990	0.919730007648468
1991	0.925740003585815
1992	0.934809982776642
1993	0.937979996204376
1994	0.949410021305084
1995	0.956960022449493
1996	0.962180018424988
1997	0.964900016784668
1998	0.970749974250793
1999	0.974529981613159
2000	0.978259980678558
2001	0.980319976806641
2002	0.980870008468628
2003	0.983650028705597
2004	0.989430010318756
2005	0.992560029029846
2006	0.995720028877258
2007	0.999180018901825
2008	1.00195002555847
2009	1.00686001777649
2010	0.995270013809204
2011	0.99702000617981
2012	1.00099003314972
2013	1.00612998008728
2014	1.0100200176239
2015	1.0077999830246
2016	1.00821995735168
2017	1.00832998752594
2018	1.00996994972229
2019	1.01059997081757
2020	1.00885999202728