Year	gross (GPI)
1975	0.857900023460388
1976	0.844070017337799
1977	0.842580020427704
1978	0.857219994068146
1979	0.873849987983704
1980	0.868019998073578
1981	0.8507199883461
1982	0.854460000991821
1983	0.866320013999939
1984	0.870630025863647
1985	0.852530002593994
1986	0.873950004577637
1987	0.889509975910187
1988	0.893209993839264
1989	0.901769995689392
1990	0.905189990997314
1991	0.912949979305267
1992	0.924109995365143
1993	0.928870022296906
1994	0.950709998607636
1995	0.959349989891052
1996	0.964200019836426
1997	0.964770019054413
1998	0.973609983921051
1999	0.978730022907257
2000	0.983399987220764
2001	0.983349978923798
2002	0.984210014343262
2003	0.987190008163452
2004	0.99576997756958
2005	1.00443005561829
2006	1.01040005683899
2007	1.01792001724243
2008	1.02546000480652
2009	1.03228998184204
2010	1.01308000087738
2011	1.01533997058868
2012	1.01669001579285
2013	1.0220400094986
2014	1.02546000480652
2015	1.02169001102448
2016	1.01864004135132
2017	1.01560997962952
2018	1.01718997955322
2019	1.01839005947113
2020	1.01730000972748