Year	gross (GPI)
1970	0.567229986190796
1971	0.563359975814819
1972	0.559620022773743
1973	0.562409996986389
1974	0.56563001871109
1975	0.556829988956451
1976	0.551919996738434
1977	0.548979997634888
1978	0.547089993953705
1979	0.545249998569489
1980	0.556509971618652
1981	0.564379990100861
1982	0.589129984378815
1983	0.594860017299652
1984	0.604619979858398
1985	0.616720020771027
1986	0.629180014133453
1987	0.641369998455048
1988	0.64740002155304
1989	0.655529975891113
1990	0.66237998008728
1991	0.669920027256012
1992	0.673099994659424
1993	0.669260025024414
1994	0.651419997215271
1995	0.682330012321472
1996	0.681879997253418
1997	0.680580019950867
1998	0.67943000793457
1999	0.684310019016266
2000	0.686429977416992
2001	0.689260005950928
2002	0.693340003490448
2003	0.705510020256042
2004	0.695649981498718
2005	0.70702999830246
2006	0.708790004253387
2007	0.719990015029907
2008	0.731149971485138
2009	0.743839979171753
2010	0.761020004749298
2011	0.782829999923706
2012	0.795610010623932
2013	0.811410009860992
2014	0.817619979381561
2015	0.83297997713089
2016	0.837459981441498
2017	0.84622997045517
2018	0.854009985923767
2019	0.855579972267151
2020	0.862450003623962