Year	gross (GPI)
1970	0.432599991559982
1971	0.426259994506836
1972	0.414059996604919
1973	0.411040008068085
1974	0.389560014009476
1975	0.403219997882843
1976	0.420989990234375
1977	0.433979988098145
1978	0.447910010814667
1979	0.416299998760223
1980	0.422089993953705
1981	0.431450009346008
1982	0.464390009641647
1983	0.42807000875473
1984	0.417629987001419
1985	0.4269799888134
1986	0.418689996004105
1987	0.453799992799759
1988	0.435669988393784
1989	0.434399992227554
1990	0.425889998674393
1991	0.425889998674393
1992	0.432649999856949
1993	0.46560999751091
1994	0.478920012712479
1995	0.49702000617981
1996	0.518010020256042
1997	0.539789974689484
1998	0.556569993495941
1999	0.587320029735565
2000	0.608990013599396
2001	0.620559990406036
2002	0.60614001750946
2003	0.59306001663208
2004	0.593999981880188
2005	0.609000027179718
2006	0.614970028400421
2007	0.604560017585754
2008	0.605220019817352
2009	0.616750001907349
2010	0.631349980831146
2011	0.64358001947403
2012	0.665329992771149
2013	0.680490016937256
2014	0.684499979019165
2015	0.688790023326874
2016	0.694220006465912
2017	0.703379988670349
2018	0.714980006217957
2019	0.723839998245239
2020	0.746720016002655
2021	0.760730028152466