Year	gross (GPI)
1970	0.790589988231659
1971	0.789210021495819
1972	0.788439989089966
1973	0.78982001543045
1974	0.791400015354156
1975	0.815209984779358
1976	0.828090012073517
1977	0.83228999376297
1978	0.836589992046356
1979	0.838850021362305
1980	0.839370012283325
1981	0.83788001537323
1982	0.835409998893738
1983	0.836579978466034
1984	0.836009979248047
1985	0.837279975414276
1986	0.851100027561188
1987	0.857460021972656
1988	0.860549986362457
1989	0.863829970359802
1990	0.867550015449524
1991	0.87431001663208
1992	0.880020022392273
1993	0.884590029716492
1994	0.891460001468658
1995	0.896189987659454
1996	0.899800002574921
1997	0.906539976596832
1998	0.913079977035522
1999	0.919709980487823
2000	0.92127001285553
2001	0.924700021743774
2002	0.927450001239777
2003	0.944840013980865
2004	0.945909976959229
2005	0.950500011444092
2006	0.954280018806458
2007	0.958429992198944
2008	0.965240001678467
2009	0.972249984741211
2010	0.97146999835968
2011	0.973749995231628
2012	0.977349996566772
2013	0.991919994354248
2014	0.994080007076263
2015	0.995039999485016
2016	0.999909996986389
2017	0.998250007629395
2018	0.987030029296875
2019	0.988049983978271
2020	0.985639989376068