Year	gross (GPI)
1971	0.951250016689301
1972	0.957729995250702
1973	0.954970002174377
1974	0.959619998931885
1975	0.954349994659424
1976	0.964060008525848
1977	1.00659000873566
1978	1.00521004199982
1979	1.00811004638672
1980	1.02098000049591
1981	1.09054005146027
1982	0.983820021152496
1984	0.978359997272491
1986	0.971790015697479
1987	0.954209983348846
1988	0.938929975032806
1990	0.936489999294281
1991	0.978799998760223
1992	1.00952005386353
1993	1.07781004905701
1994	1.11768996715546
1995	1.14623999595642
1999	1.03421998023987
2000	1.01900005340576
2001	1.01148998737335
2002	0.999140024185181
2003	1.00506997108459
2004	0.999040007591248
2005	1.0013200044632
2006	0.989430010318756
2007	0.970870018005371
2008	0.973420023918152
2009	0.973749995231628
2010	0.982879996299744
2011	0.994170010089874
2012	0.979489982128143
2013	0.983990013599396
2014	1.0050300359726
2015	0.984170019626617
2016	0.973370015621185
2017	0.956953406333923
2019	0.967760026454926
2020	0.932869970798492
2021	0.954649984836578