Year	gross (GPI)
1971	0.40226998925209
1972	0.410400003194809
1975	0.467660009860992
1976	0.504029989242554
1977	0.528580009937286
1978	0.552280008792877
1979	0.577160000801086
1980	0.64055997133255
1981	0.686230003833771
1982	0.728879988193512
1983	0.753139972686768
1984	0.75738000869751
1985	0.733940005302429
1986	0.727630019187927
1987	0.751309990882874
1988	0.782509982585907
1989	0.804780006408691
1990	0.818690001964569
1991	0.826879978179932
1992	0.861410021781921
1993	0.879670023918152
1994	0.88358998298645
1995	0.920400023460388
1996	0.931779980659485
1997	0.959659993648529
1998	0.976480007171631
1999	1.0030699968338
2000	1.02822995185852
2001	1.05074000358582
2002	1.06113004684448
2003	1.07597994804382
2004	1.06991994380951
2005	1.07091999053955
2006	1.07604002952576
2007	1.08791995048523
2008	1.09292995929718
2009	1.09959995746613
2010	1.10100996494293
2011	1.09917998313904
2012	1.08034002780914
2015	1.11700999736786
2016	1.10703003406525
2017	1.11951994895935
2018	1.11073005199432
2020	1.12698996067047
2021	1.14196002483368