Year	gross (GPI)
1970	0.624750018119812
1971	0.628709971904755
1972	0.645929992198944
1973	0.649360001087189
1974	0.651189982891083
1975	0.657970011234283
1976	0.664749979972839
1977	0.686710000038147
1978	0.710550010204315
1979	0.717079997062683
1980	0.729349970817566
1981	0.74769002199173
1982	0.761520028114319
1983	0.747139990329742
1984	0.761340022087097
1985	0.763459980487823
1986	0.768459975719452
1987	0.77293998003006
1988	0.774529993534088
1989	0.788760006427765
1990	0.785939991474152
1991	0.796859979629517
1992	0.804109990596771
1993	0.806509971618652
1994	0.812150001525879
1995	0.810079991817474
1996	0.814310014247894
1997	0.818400025367737
1998	0.820360004901886
1999	0.83008998632431
2000	0.838590025901794
2001	0.846289992332459
2002	0.847509980201721
2003	0.860199987888336
2004	0.860360026359558
2005	0.879329979419708
2006	0.894020020961761
2007	0.906549990177155
2008	0.913299977779388
2009	0.921199977397919
2010	0.928919970989227
2011	0.936230003833771
2012	0.945420026779175
2013	0.947610020637512
2014	0.947830021381378
2015	0.951380014419556
2016	0.947380006313324
2017	0.949000000953674
2018	0.94734001159668
2019	0.951520025730133
2020	0.951860010623932