Year	gross (GPI)
1971	0.47036001086235
1972	0.483489990234375
1973	0.541329979896545
1974	0.566259980201721
1975	0.574599981307983
1976	0.593739986419678
1977	0.609990000724792
1978	0.605170011520386
1979	0.61829000711441
1980	0.620220005512238
1981	0.62133002281189
1982	0.607990026473999
1983	0.616890013217926
1984	0.636619985103607
1985	0.661130011081696
1986	0.683319985866547
1987	0.714219987392426
1988	0.75670999288559
1989	0.773310005664825
1990	0.781930029392242
1991	0.811129987239838
1992	0.794040024280548
1993	0.796620011329651
2003	0.797299981117249
2004	0.818379998207092
2005	0.837559998035431
2006	0.884220004081726
2007	0.898490011692047
2009	0.926129996776581
2010	0.938820004463196
2011	0.95414000749588
2012	0.963710010051727
2013	0.972280025482178
2014	0.992950022220612
2015	1.00404000282288
2016	1.01382005214691
2017	1.02148997783661
2018	1.03429996967316
2019	1.04294002056122
2020	1.05725002288818