Year	gross (GPI)
1970	0.949329972267151
1971	0.958100020885468
1972	0.930350005626678
1973	0.911750018596649
1974	0.909330010414124
1975	0.919170022010803
1976	0.904100000858307
1977	0.923720002174377
1978	0.939689993858337
1979	0.959760010242462
1980	0.986800014972687
1981	1.02891004085541
1982	1.02926003932953
1983	1.0377299785614
1984	1.02959001064301
1985	1.0557199716568
1986	1.08345997333527
1987	1.10283005237579
1988	1.11539995670319
1989	1.11765003204346
1990	1.14732003211975
1991	1.16560995578766
1992	1.15197002887726
1993	1.16907000541687
1994	1.21080994606018
1995	1.26644003391266
1996	1.30083000659943
1997	1.33840000629425
1998	1.38120996952057
1999	1.41835999488831
2000	1.45644998550415
2001	1.48067998886108
2002	1.50221002101898
2003	1.51031005382538
2004	1.48547005653381
2005	1.4804300069809
2006	1.48362004756927
2007	1.48098003864288
2008	1.47434997558594
2009	1.49278998374939
2010	1.49759995937347
2011	1.49669003486633
2012	1.46480000019073
2013	1.49146997928619
2014	1.45414996147156
2015	1.41923999786377
2016	1.42431998252869