Year	gross (GPI)
1970	1.07056999206543
1971	1.086629986763
1972	1.09931004047394
1973	1.13110995292664
1974	1.10280001163483
1975	1.10889995098114
1976	1.13295996189117
1977	1.1468700170517
1979	1.14837002754211
1980	1.15964996814728
1981	1.13745999336243
1982	1.13005995750427
1983	1.12531995773315
1984	1.09535002708435
1985	1.09309995174408
1986	1.06717002391815
1987	1.05219995975494
1988	1.03795003890991
1989	1.02947998046875
1990	1.04112005233765
1991	1.05297994613647
1992	1.05481004714966
1993	1.07444000244141
1994	1.07571005821228
1995	1.08012998104095
1996	1.0900399684906
1997	1.10322999954224
1998	1.07445001602173
1999	1.08290994167328
2000	1.07486999034882
2001	1.06167995929718
2002	1.06037998199463
2004	1.04325997829437
2005	1.04335999488831
2006	1.04553997516632
2007	1.03480005264282
2008	1.04279005527496
2009	1.04605996608734
2010	1.04220998287201
2011	1.04072999954224
2012	1.04000997543335
2013	1.05904996395111
2014	1.05491995811462
2015	1.04027998447418
2016	1.0541900396347
2017	1.0718799829483
2018	1.07530999183655
2019	1.07574999332428
2020	1.08633995056152