Year	gross (GPI)
1971	0.484019994735718
1972	0.498039990663528
1973	0.558560013771057
1974	0.586059987545013
1975	0.595879971981049
1976	0.618659973144531
1977	0.63154000043869
1978	0.62830001115799
1979	0.642709970474243
1980	0.641569972038269
1981	0.643029987812042
1982	0.613550007343292
1983	0.630129992961884
1984	0.651120007038116
1985	0.676549971103668
1986	0.703149974346161
1987	0.733479976654053
1988	0.777509987354279
1989	0.794040024280548
1990	0.801169991493225
1991	0.836570024490356
1992	0.817089974880219
1993	0.819119989871979
1995	0.801429986953735
1996	0.849960029125214
1997	0.842899978160858
1998	0.815129995346069
1999	0.789200007915497
2000	0.796970009803772
2001	0.793950021266937
2002	0.780260026454926
2003	0.801660001277924
2004	0.829500019550323
2005	0.855790019035339
2006	0.908490002155304
2007	0.928600013256073
2008	0.950119972229004
2009	0.96780002117157
2010	0.988659977912903
2011	1.00662994384766
2012	1.01582002639771
2013	1.01944994926453
2014	1.03279995918274
2015	1.02955996990204
2016	1.02292001247406
2017	1.01498997211456
2018	1.01250004768372
2019	1.01482999324799
2020	1.01317000389099