Year	gross (GPI)
1970	0.810750007629395
1971	0.825810015201569
1972	0.8298100233078
1973	0.828580021858215
1974	0.843020021915436
1975	0.845939993858337
1976	0.850629985332489
1977	0.853540003299713
1978	0.841390013694763
1979	0.839810013771057
1980	0.842580020427704
1981	0.849629998207092
1982	0.86615002155304
1983	0.85658997297287
1993	0.86760002374649
1996	0.865629971027374
1998	0.875100016593933
1999	0.866389989852905
2000	0.897010028362274
2001	0.904659986495972
2002	0.911300003528595
2004	0.923690021038055
2005	0.930589973926544
2006	0.938380002975464
2007	0.946510016918182
2008	0.954259991645813
2009	0.96425998210907
2010	0.966210007667542
2011	0.966910004615784
2012	0.96424001455307
2013	0.959980010986328
2014	0.9619500041008
2015	0.95890998840332
2016	0.959710001945496
2017	0.962559998035431
2018	0.966359972953796
2019	0.971830010414124
2020	0.980570018291473
2021	0.994180023670197