Year	gross (GPI)
1971	0.549639999866486
1972	0.551569998264313
1973	0.559400022029877
1974	0.575919985771179
1975	0.577690005302429
1976	0.56919002532959
1977	0.566299974918365
1978	0.565819978713989
1979	0.610249996185303
1980	0.58051997423172
1981	0.576189994812012
1982	0.584959983825684
1983	0.596650004386902
1984	0.575100004673004
1985	0.58118999004364
1986	0.585259974002838
1987	0.576560020446777
1988	0.567449986934662
1989	0.58407998085022
1990	0.592779994010925
1991	0.594889998435974
1992	0.602419972419739
1993	0.605710029602051
1994	0.574859976768494
1995	0.622510015964508
1996	0.62475997209549
1997	0.638189971446991
1998	0.652520000934601
1999	0.668049991130829
2000	0.675360023975372
2001	0.68273001909256
2002	0.68436998128891
2003	0.694149971008301
2004	0.700500011444092
2005	0.715210020542145
2006	0.724560022354126
2007	0.73717999458313
2008	0.772949993610382
2009	0.787140011787415
2010	0.80774998664856
2011	0.819289982318878
2012	0.832989990711212
2013	0.836939990520477
2014	0.847649991512299
2015	0.84672999382019
2016	0.853169977664948
2017	0.864979982376099
2018	0.864385008811951
2019	0.87730997800827
2020	0.898125231266022
2021	0.912519991397858