Year	gross (GPI)
1971	0.426860004663467
1973	0.433180004358292
1974	0.441000014543533
1975	0.482289999723434
1977	0.378320008516312
1985	0.41091001033783
1986	0.397150009870529
1987	0.402709990739822
1999	0.460979998111725
2000	0.457639992237091
2001	0.4723100066185
2002	0.472689986228943
2003	0.467150002717972
2004	0.471179991960526
2011	0.623480021953583
2013	0.670080006122589
2014	0.689710021018982
2015	0.714070022106171
2016	0.75559002161026
2020	0.809300005435944
2021	0.831520020961761