Year	gross (GPI)
1971	1.06591999530792
1972	1.07165002822876
1973	1.09589004516602
1974	1.13256001472473
1975	1.13680994510651
1984	1.24408996105194
1985	1.25617003440857
1986	1.23227000236511
1987	1.23520004749298
1988	1.23055994510651
1989	1.23713004589081
1991	1.24015998840332
1992	1.2406200170517
1993	1.24875998497009
1999	1.22622001171112
2000	1.19964003562927
2001	1.17510998249054
2002	1.16194999217987
2003	1.15086996555328
2004	1.13995003700256
2005	1.13028001785278
2006	1.12556004524231
2007	1.11647999286652
2008	1.10140001773834
2009	1.09311997890472
2010	1.09621000289917
2011	1.09371995925903
2012	1.09325003623962
2013	1.09049999713898
2014	1.07729995250702
2015	1.07729005813599
2016	1.07924997806549
2017	1.0806200504303