Year	gross (GPI)
1978	0.109470002353191
1979	0.191200003027916
1980	0.0757699981331825
1981	0
1982	0.0825600028038025
1983	0.0385099984705448
1984	0.456310003995895
1985	0.720489978790283
1986	0.66838002204895
1987	0.74168998003006
1988	0.786979973316193
1989	1.04328000545502
1990	1.11866998672485
1991	1.15146994590759
1992	1.26135003566742
1993	1.25044000148773
1994	1.30429995059967
1995	1.22474002838135
1996	1.14300000667572
1997	1.08765995502472
1998	1.01177000999451
2003	0.743990004062653
2004	1.11353003978729
2005	1.1108900308609
2006	1.10164999961853
2007	1.12167000770569
2009	1.25949001312256
2010	1.15805995464325
2011	1.17607998847961
2013	1.32087004184723
2014	1.38534998893738
2015	1.40032994747162
2016	1.44588005542755
2017	1.42309999465942
2018	1.40119004249573
2019	1.36631000041962
2020	1.32335996627808
2021	1.3216700553894