Year	gross (GPI)
1970	0.764540016651154
1971	0.763000011444092
1972	0.76283997297287
1973	0.771239995956421
1974	0.783519983291626
1975	0.796320021152496
1976	0.801490008831024
1977	0.807330012321472
1978	0.821049988269806
1979	0.827499985694885
1980	0.824859976768494
1981	0.819909989833832
1982	0.816670000553131
1983	0.825860023498535
1984	0.816690027713776
1985	0.811190009117126
1986	0.827660024166107
1987	0.83568000793457
1988	0.83841997385025
1989	0.843429982662201
1990	0.84485000371933
1991	0.84987998008728
1992	0.855260014533997
1993	0.858829975128174
1994	0.87033998966217
1995	0.879239976406097
1996	0.885089993476868
1997	0.893980026245117
1998	0.90666002035141
1999	0.916819989681244
2000	0.919560015201569
2001	0.921299993991852
2002	0.925209999084473
2003	0.938950002193451
2004	0.94037002325058
2005	0.947440028190613
2006	0.950479984283447
2007	0.956120014190674
2008	0.962819993495941
2009	0.972790002822876
2010	0.967739999294281
2011	0.970600008964539
2012	0.973489999771118
2013	0.985220015048981
2014	0.989809989929199
2015	0.989560008049011
2016	0.990409970283508
2017	0.989459991455078
2018	0.992439985275269
2019	0.992910027503967
2020	0.988680005073547