Year	gross (GPI)
1976	0.944859981536865
1978	0.955869972705841
1979	0.955630004405975
1980	0.967570006847382
1981	0.964119970798492
1982	0.972299993038177
1983	0.988390028476715
1984	0.972959995269775
1985	0.98444002866745
1986	0.991509974002838
1987	0.976859986782074
1988	1.00966000556946
1989	1.00603997707367
1990	1.00459003448486
1991	1.00398004055023
1992	1.01642000675201
1993	1.03497004508972
1994	0.987640023231506
1995	0.968670010566711
1996	0.973850011825562
1997	0.966279983520508
1998	0.969470024108887
1999	0.981459975242615
2000	0.997169971466064
2001	1.0153900384903
2002	0.994340002536774
2003	1.00943994522095
2004	1.01349997520447
2005	1.00536000728607
2006	1.0084400177002
2007	1.0077600479126
2008	1.00249004364014
2009	0.997179985046387
2010	1.00642001628876
2011	1.01557004451752
2012	1.01601004600525
2013	1.0222100019455
2014	1.03682005405426
2015	1.03129994869232
2016	1.03554999828339
2017	1.03224003314972
2018	1.03764998912811
2019	1.029629945755
2020	1.02745997905731
2021	1.01776003837585