Year	gross (GPI)
1971	0.826370000839233
1973	0.857200026512146
1975	0.879260003566742
1977	0.895980000495911
1978	0.920369982719421
1979	0.932550013065338
1980	0.960590004920959
1981	1.10469996929169
1982	0.91032999753952
1983	0.920099973678589
1984	0.946009993553162
1986	0.935109972953796
1987	0.900089979171753
1988	0.924979984760284
1989	0.932550013065338
1990	0.963660001754761
1991	1.00011003017426
1993	1.0876499414444
1998	1.25394999980927
1999	1.29874002933502
2000	1.28338003158569
2001	1.26485002040863
2002	1.259889960289
2003	1.23660004138947
2004	1.24200999736786
2005	1.24811995029449
2006	1.21840000152588
2007	1.24160003662109
2008	1.2325199842453
2009	1.2340099811554
2010	1.23211002349854
2011	1.24528002738953
2012	1.24179995059967
2013	1.25431001186371
2014	1.2514899969101
2015	1.27128005027771
2016	1.27811002731323
2017	1.28219997882843
2018	1.28968000411987
2019	1.32216000556946
2020	1.31061005592346
2021	1.30814003944397