Year	gross (GPI)
1973	1.03872001171112
1974	1.03673994541168
1975	1.0424200296402
1976	1.0474100112915
1977	1.04396998882294
1978	1.03956997394562
1979	1.04619002342224
1980	1.05010998249054
1983	1.03824996948242
1984	1.0472799539566
1985	1.04905998706818
1986	1.04938995838165
1987	1.04412996768951
1988	1.05086994171143
1989	1.04024994373322
1990	1.04474997520447
1991	1.0404200553894
1992	1.02548003196716
1993	1.02699995040894
1994	1.0188000202179
1999	0.990620017051697
2000	0.995169997215271
2001	0.995660006999969
2002	0.991530001163483
2003	0.987760007381439
2004	0.999059975147247
2005	0.999939978122711
2006	1.0025999546051
2007	1.00650000572205
2008	1.01152002811432
2009	1.01291000843048
2010	1.01357996463776
2011	1.01201999187469
2012	1.01203000545502
2013	1.01078999042511
2014	1.00927996635437
2015	1.00824999809265
2016	1.0129599571228
2017	1.01277005672455
2018	1.01285004615784
2019	1.01429998874664
2020	1.01328003406525