Year	gross (GPI)
1970	0.660120010375977
1971	0.661620020866394
1972	0.672309994697571
1973	0.677500009536743
1974	0.686439990997314
1975	0.690419971942902
1976	0.696030020713806
1977	0.70771998167038
1978	0.723559975624084
1979	0.729120016098022
1980	0.740790009498596
1981	0.749440014362335
1982	0.776080012321472
1983	0.781080007553101
1984	0.788010001182556
1985	0.778580009937286
1986	0.78438001871109
1987	0.799310028553009
1988	0.79000997543335
1989	0.794809997081757
1990	0.798179984092712
1991	0.805069983005524
1992	0.809239983558655
1993	0.812009990215302
1994	0.813780009746552
1995	0.799070000648499
1996	0.793269991874695
1997	0.798870027065277
1998	0.800700008869171
1999	0.82134997844696
2000	0.830560028553009
2001	0.835539996623993
2002	0.836409986019135
2003	0.84605997800827
2004	0.8439000248909
2005	0.868560016155243
2006	0.882740020751953
2007	0.888109982013702
2008	0.897629976272583
2009	0.909439980983734
2010	0.917219996452332
2011	0.922839999198914
2012	0.927519977092743
2013	0.931949973106384
2014	0.933499991893768
2015	0.941380023956299
2016	0.94310998916626
2017	0.942369997501373
2018	0.939710021018982
2019	0.942839980125427
2020	0.946569979190826