Year	gross (GPI)
1970	0.676569998264313
1971	0.676530003547668
1972	0.656599998474121
1973	0.643180012702942
1974	0.628949999809265
1975	0.618839979171753
1976	0.609359979629517
1977	0.596080005168915
1978	0.577040016651154
1979	0.557190001010895
1980	0.548820018768311
1981	0.538150012493134
1982	0.531949996948242
1983	0.529659986495972
1984	0.52827000617981
1985	0.521619975566864
1986	0.52318000793457
1987	0.538839995861053
1988	0.52156001329422
1989	0.51867002248764
1990	0.517000019550323
1991	0.53591001033783
1992	0.555469989776611
1993	0.570259988307953
1994	0.605130016803741
1995	0.615920007228851
1996	0.630509972572327
1997	0.644339978694916
1998	0.665859997272491
1999	0.689490020275116
2000	0.693750023841858
2001	0.690180003643036
2002	0.697109997272491
2003	0.68352997303009
2004	0.694140017032623
2005	0.696789979934692
2006	0.708249986171722
2007	0.708679974079132
2008	0.702009975910187
2009	0.709280014038086
2010	0.705690026283264
2011	0.690550029277802
2012	0.712300002574921
2013	0.721480011940002
2014	0.720200002193451
2015	0.729770004749298
2016	0.741029977798462
2017	0.749660015106201
2018	0.762419998645782
2019	0.773819983005524
2020	0.787370026111603
2021	0.789080023765564