Year	gross (GPI)
1971	0.431259989738464
1972	0.446859985589981
1973	0.454759985208511
1974	0.466919988393784
1975	0.474429994821548
1976	0.491059988737106
1977	0.501420021057129
1978	0.519159972667694
1979	0.537220001220703
1980	0.546909987926483
1982	0.569180011749268
1983	0.574710011482239
1984	0.56862998008728
1985	0.561209976673126
1986	0.552079975605011
1987	0.554499983787537
1988	0.559490025043488
1989	0.56563001871109
1990	0.578580021858215
1991	0.587140023708344
1992	0.593240022659302
1994	0.595040023326874
1995	0.608839988708496
1996	0.616850018501282
1997	0.632700026035309
1999	0.669920027256012
2000	0.691349983215332
2001	0.700890004634857
2002	0.714150011539459
2003	0.72189998626709
2004	0.735480010509491
2005	0.744239985942841
2006	0.756460011005402
2007	0.755240023136139
2017	0.87474000453949
2021	0.910440027713776