Year	gross (GPI)
1970	0.935230016708374
1971	0.928520023822784
1972	0.935639977455139
1973	0.942520022392273
1974	0.944790005683899
1975	0.950010001659393
1976	0.968330025672913
1977	0.987800002098084
1978	0.994989991188049
1979	1.00171995162964
1980	0.989009976387024
1981	1.00088000297546
1982	1.00522005558014
1983	1.00657999515533
1984	1.00146996974945
1991	0.998749971389771
1992	1.01400005817413
1993	1.01660001277924
1994	1.00407004356384
1998	0.985050022602081
1999	0.981339991092682
2000	0.982150018215179
2001	0.977370023727417
2002	0.973049998283386
2003	0.97886997461319
2004	0.972670018672943
2005	0.972459971904755
2006	0.978129982948303
2007	0.982819974422455
2008	0.987770020961761
2009	0.99329000711441
2010	1.00109994411469
2011	0.998149991035461
2012	1.0095499753952
2013	1.01909005641937
2014	1.01016998291016
2015	0.998702049255371
2016	1.01419997215271
2017	1.01496005058289
2018	1.01620995998383
2019	1.02144002914429
2020	1.01873004436493