Year	gross (GPI)
1971	0.343549996614456
1973	0.292250007390976
1981	0.520099997520447
1986	0.645709991455078
1987	0.674170017242432
1999	0.817210018634796
2002	0.851270020008087
2003	0.839680016040802
2004	0.762419998645782
2013	1.03761994838715
2014	1.0683399438858
2017	1.06203997135162
2018	1.06648004055023