Year	gross (GPI)
1971	0.92509001493454
1972	0.938809990882874
1973	0.941559970378876
1974	0.949419975280762
1975	0.965290009975433
1976	0.964470028877258
1977	0.964510023593903
1978	0.971379995346069
1979	0.985210001468658
1980	0.885930001735687
1986	1.00645995140076
1988	0.959869980812073
1990	0.970719993114471
1991	1.02751994132996
1993	1.04068005084991
1994	1.0166699886322
1995	1.01528000831604
1996	1.02113997936249
1998	1.0168000459671
1999	1.01848995685577
2000	1.0108699798584
2001	1.01960003376007
2002	1.00531005859375
2003	1.0174800157547
2004	1.01954996585846
2005	1.01918995380402
2006	1.01329004764557
2007	1.00504994392395
2008	0.997699975967407
2009	1.00302994251251
2010	0.998390018939972
2011	0.994679987430573
2012	0.985260009765625
2013	0.975929975509644
2014	0.968249976634979
2015	0.966910004615784
2016	0.969929993152618
2017	0.974430024623871
2018	0.986050009727478
2019	0.993099987506866
2020	0.997269988059998