Year	gross (GPI)
1970	0.692619979381561
1971	0.682709991931915
1972	0.710080027580261
1974	0.781539976596832
1979	0.927420020103455
1980	0.953519999980927
1981	0.972220003604889
1982	0.989849984645844
1983	0.993749976158142
1984	1.00777995586395
1985	1.01569998264313
1986	1.00352001190186
1987	1.02518999576569
1988	1.03620994091034
1989	1.04331994056702
1990	1.07214999198914
1991	1.05434000492096
1992	1.06640994548798
1993	1.07264995574951
1994	1.08385002613068
1995	1.09231996536255
1997	1.07217001914978
1998	1.09209001064301
1999	1.08319997787476
2000	1.0918300151825
2001	1.08819997310638
2002	1.09688997268677
2003	1.12862002849579
2004	1.12647998332977
2005	1.10303997993469
2006	1.09063005447388
2007	1.08252000808716
2008	1.08425998687744
2009	1.08033001422882
2010	1.07670998573303
2011	1.08398997783661
2012	1.04823994636536
2013	1.06254994869232
2014	1.08219003677368
2015	1.08940005302429
2016	1.0688099861145
2017	1.05843997001648
2018	1.08428001403809
2019	1.07804000377655
2020	1.07194995880127
2021	1.0560075044632