Year	gross (GPI)
1970	0.689249992370605
1971	0.687340021133423
1972	0.684849977493286
1973	0.689880013465881
1974	0.689580023288727
1975	0.679669976234436
1976	0.671999990940094
1977	0.665109992027283
1978	0.664170026779175
1979	0.653930008411407
1980	0.644689977169037
1981	0.648710012435913
1982	0.654770016670227
1983	0.616620004177094
1984	0.59469997882843
1985	0.650950014591217
1986	0.713360011577606
1987	0.734950006008148
1988	0.739750027656555
1989	0.747640013694763
1990	0.760380029678345
1991	0.770129978656769
1992	0.779640018939972
1993	0.785059988498688
1994	0.78684002161026
1995	0.805260002613068
1996	0.812340021133423
1997	0.815819978713989
1998	0.815819978713989
1999	0.817179977893829
2000	0.802200019359589
2001	0.796750009059906
2002	0.777079999446869
2003	0.783670008182526
2004	0.78100997209549
2005	0.787810027599335
2006	0.786140024662018
2007	0.777750015258789
2008	0.797049999237061
2009	0.809880018234253
2010	0.821439981460571
2011	0.828100025653839
2012	0.847760021686554
2013	0.861259996891022
2014	0.862240016460419
2015	0.867780029773712
2016	0.87458997964859
2017	0.88484001159668
2018	0.892809987068176
2019	0.893989980220795
2020	0.900279998779297