Year	gross (GPI)
1971	0.723760008811951
1972	0.851779997348785
1973	0.887030005455017
1974	0.940789997577667
1975	0.947009980678558
1976	0.961160004138947
1977	0.943899989128113
1978	0.9235799908638
1979	0.859939992427826
1980	0.848619997501373
1981	0.808979988098145
1982	0.847880005836487
1983	0.861140012741089
1984	0.910449981689453
1985	0.924549996852875
1986	0.954739987850189
1987	0.956709980964661
1988	0.972649991512299
1989	1.00802004337311
1990	1.02330994606018
1991	1.04288995265961
1992	1.07088005542755
1993	1.06665003299713
1994	1.05799996852875
1995	1.03949999809265
1996	1.04990994930267
1997	1.08124995231628
1998	1.0720100402832
1999	1.06944000720978
2000	1.04953002929688
2001	1.07339000701904
2002	1.12023997306824
2003	1.12036001682281
2004	1.10965001583099
2005	1.10915005207062
2006	1.09776997566223
2008	1.08077001571655
2009	1.04886996746063
2010	1.01398003101349
2011	0.977240025997162
2012	1.0184600353241
2013	1.01188004016876
2014	1.00560998916626
2015	0.993110001087189
2016	1.0081399679184
2017	1.03585994243622
2018	1.0613499879837
2019	1.08899998664856