Year	gross (GPI)
1971	0.445789992809296
1972	0.454230010509491
1973	0.457109987735748
1974	0.448449999094009
1975	0.441240012645721
1976	0.460130006074905
1977	0.453319996595383
1978	0.469330012798309
1979	0.471689999103546
1980	0.509400010108948
1981	0.473780006170273
1982	0.478139996528625
1983	0.483859986066818
1984	0.497830003499985
1985	0.500140011310577
1986	0.506190001964569
1987	0.508960008621216
1988	0.511730015277863
1989	0.514429986476898
1990	0.517300009727478
1991	0.503430008888245
1992	0.511409997940063
1993	0.522909998893738
1994	0.550589978694916
1995	0.565819978713989
1996	0.583639979362488
1997	0.604210019111633
1998	0.634790003299713
1999	0.659870028495789
2000	0.685660004615784
2001	0.697329998016357
2002	0.718450009822845
2003	0.736899971961975
2004	0.766409993171692
2005	0.791209995746613
2006	0.819700002670288
2008	0.858399987220764
2009	0.876020014286041
2010	0.89164000749588
2011	0.894900023937225
2012	0.907239973545074
2013	0.915210008621216
2014	0.92426997423172
2015	0.930239975452423
2016	0.936269998550415
2017	0.935029983520508
2018	0.937330007553101
2019	0.929679989814758
2020	0.925499975681305
2021	0.925650000572205