Year	gross (GPI)
1971	0.408859997987747
1972	0.421139985322952
1978	0.469119995832443
1979	0.481189996004105
1980	0.486649990081787
1981	0.493259996175766
1982	0.513759970664978
1983	0.499330013990402
1984	0.492529988288879
1985	0.499139994382858
1986	0.496980011463165
1988	0.506770014762878
1989	0.498450011014938
1990	0.509490013122559
1992	0.533680021762848
1996	0.605340003967285
1997	0.60045999288559
1998	0.617399990558624
1999	0.64190000295639
2000	0.650259971618652
2001	0.659200012683868
2002	0.669250011444092
2004	0.720510005950928
2005	0.746640026569366
2006	0.759050011634827
2008	0.790709972381592
2010	0.87269002199173
2011	0.918290019035339
2012	0.941690027713776
2013	0.96850997209549
2014	0.995779991149902
2015	1.02227377891541
2019	1.13162004947662
2020	1.16217994689941
2021	1.2002899646759