Year	gross (GPI)
1970	0.625199973583221
1971	0.631820023059845
1972	0.644219994544983
1973	0.654709994792938
1974	0.669700026512146
1975	0.680079996585846
1976	0.686219990253448
1977	0.712270021438599
1978	0.733210027217865
1979	0.751860022544861
1980	0.767470002174377
1981	0.779129981994629
1982	0.797320008277893
1983	0.792490005493164
1984	0.79475998878479
1985	0.794080018997192
1986	0.799870014190674
1987	0.813390016555786
1988	0.791670024394989
1989	0.813769996166229
1990	0.800809979438782
1991	0.809449970722198
1992	0.810029983520508
1993	0.80842000246048
1994	0.816479980945587
1995	0.811850011348724
1996	0.81647002696991
1997	0.818260014057159
1998	0.815750002861023
1999	0.824270009994507
2000	0.830590009689331
2001	0.836549997329712
2002	0.833599984645844
2003	0.843190014362335
2004	0.837890028953552
2005	0.855329990386963
2006	0.866800010204315
2007	0.875649988651276
2008	0.88357001543045
2009	0.892579972743988
2010	0.90091997385025
2011	0.901939988136292
2012	0.916809976100922
2013	0.924870014190674
2014	0.931860029697418
2015	0.940789997577667
2016	0.936519980430603
2017	0.939180016517639
2018	0.940180003643036
2019	0.940159976482391
2020	0.94047999382019