Year	gross (GPI)
1971	0.445650011301041
1973	0.45456001162529
1974	0.446359992027283
1975	0.44530001282692
1977	0.439790010452271
1985	0.478969991207123
1986	0.482289999723434
1987	0.486829996109009
1999	0.614619970321655
2000	0.63332998752594
2001	0.646290004253387
2002	0.661450028419495
2003	0.67315000295639
2004	0.694509983062744
2011	0.809689998626709
2013	0.834890007972717
2014	0.847899973392487
2015	0.859269976615906
2016	0.877080023288727
2020	0.890009999275208
2021	0.897289991378784