Year	gross (GPI)
1970	0.758629977703094
1971	0.757439970970154
1972	0.780380010604858
1973	1.03176999092102
1974	1.06366002559662
1975	1.0150500535965
1976	1.0694899559021
1977	1.0825400352478
1978	1.14348995685577
1979	1.17211997509003
1980	1.19739997386932
1981	1.16824996471405
1982	1.19806003570557
1983	1.30975997447968
1984	1.23127996921539
1985	1.27988994121552
1987	1.34922003746033
1988	1.27979004383087
1994	1.33112001419067
1998	1.35325002670288
1999	1.37307000160217
2000	1.40945994853973
2001	1.4166100025177
2002	1.41058003902435
2003	1.37150001525879
2004	1.39827001094818
2005	1.38674998283386
2006	1.38101005554199
2007	1.37221002578735
2008	1.34843003749847
2009	1.34526002407074
2010	1.34713995456696
2011	1.35455000400543
2012	1.35440003871918
2014	1.37089002132416
2015	1.36618995666504
2016	1.36616003513336
2020	1.35763001441956
2021	1.37136995792389