Year	gross (GPI)
1971	0.287809997797012
1972	0.330320000648499
1973	0.319609999656677
1974	0.340440005064011
1976	0.357540011405945
1978	0.382869988679886
1979	0.392419993877411
1980	0.396230012178421
1981	0.414920002222061
1982	0.398110002279282
1983	0.391600012779236
1984	0.407799988985062
1987	0.436679989099503
1988	0.417349994182587
1989	0.495029985904694
1990	0.500710010528564
1991	0.515670001506805
1992	0.457910001277924
1993	0.505360007286072
1994	0.494789987802505
1995	0.494010001420975
1996	0.518459975719452
1997	0.496719986200333
1998	0.510320007801056
1999	0.53328001499176
2000	0.557900011539459
2003	0.545159995555878
2004	0.595229983329773
2005	0.616400003433228
2006	0.615409970283508
2007	0.657989978790283
2008	0.645439982414246
2009	0.655659973621368
2010	0.687390029430389
2011	0.698740005493164
2013	0.782620012760162
2014	0.741140007972717
2015	0.792569994926453
2016	0.743889987468719
2017	0.808340013027191
2018	0.822969973087311
2020	0.876078486442566