Year	gross (GPI)
1971	0.772520005702972
1972	0.765550017356873
1973	0.759999990463257
1974	0.764930009841919
1975	0.766569972038269
1976	0.760779976844788
1977	0.772419989109039
1978	0.797670006752014
1979	0.795809984207153
1980	0.787360012531281
1981	0.767409980297089
1982	0.765860021114349
1983	0.779470026493073
1984	0.787060022354126
1985	0.797439992427826
1986	0.796450018882751
1987	0.817569971084595
1988	0.820580005645752
1989	0.830470025539398
1990	0.832499980926514
1991	0.837499976158142
1992	0.851230025291443
1993	0.857829988002777
1994	0.886680006980896
1995	0.900139987468719
1996	0.91143000125885
1997	0.916410028934479
1998	0.930939972400665
1999	0.944980025291443
2000	0.951499998569489
2001	0.955039978027344
2002	0.958490014076233
2003	0.962369978427887
2004	0.973749995231628
2005	0.984809994697571
2006	0.994729995727539
2007	1.00006997585297
2008	1.00574004650116
2009	1.01348996162415
2010	0.997409999370575
2011	1.00073003768921
2012	1.00710999965668
2013	1.00539994239807
2014	1.01212000846863
2015	1.01245999336243
2016	1.01653003692627
2017	1.01724994182587
2018	1.02074003219604
2019	1.02023005485535
2020	1.01823997497559