Year	gross (GPI)
1971	0.359670013189316
1972	0.383839994668961
1973	0.43970000743866
1974	0.475010007619858
1975	0.551129996776581
1976	0.617280006408691
1977	0.679000020027161
1978	0.739080011844635
1981	1.05325996875763
1983	1.07658004760742
1984	1.11603999137878
1986	1.22450995445251
1989	1.2331999540329
1990	1.24173998832703
1991	1.28080999851227
1992	1.31377005577087
1993	1.28455996513367
1994	1.29495000839233
1995	1.29065001010895
1996	1.32032001018524
1997	1.31353998184204
1998	1.35456001758575
1999	1.4054000377655
2000	1.39689004421234
2001	1.4146900177002
2002	1.4273099899292
2003	1.44684994220734
2004	1.46808004379272
2005	1.48141002655029
2006	1.46429002285004
2007	1.46018004417419
2008	1.47461998462677
2009	1.46877002716064
2010	1.43844997882843
2011	1.41842997074127
2012	1.42868995666504
2013	1.42796003818512
2014	1.42588996887207
2015	1.4431699514389
2016	1.46226000785828
2017	1.46685004234314
2018	1.46755003929138
2019	1.4949699640274
2020	1.49460995197296
2021	1.50685000419617