Year	gross (GPI)
1970	0.983630001544952
1971	0.982540011405945
1972	0.98676997423172
1973	0.996580004692078
1974	1.00364005565643
1975	1.0095100402832
1976	1.01273000240326
1977	1.01534998416901
1979	1.02470004558563
1980	1.0215699672699
1981	1.0237900018692
1982	1.03303003311157
1983	1.02400994300842
1984	1.01803994178772
1985	1.02226996421814
1986	1.01021003723145
1987	1.00880002975464
1988	1.0048999786377
1989	1.00624001026154
1990	1.00393998622894
1991	1.00436997413635
1992	0.9930499792099
1993	1.00128996372223
1994	1.02478003501892
1995	0.98403000831604
1996	1.0513299703598
1997	1.04837000370026
1998	1.05948996543884
1999	1.0519700050354
2000	1.0586199760437
2002	1.10874998569489
2003	1.09860002994537
2004	1.05580997467041
2005	1.05557000637054
2006	1.04402995109558
2007	1.02461004257202
2008	1.04701995849609
2009	1.02880001068115
2010	1.0461699962616
2011	1.05647003650665
2012	1.06060004234314
2013	1.06851994991302
2014	1.06445002555847
2015	1.05922996997833
2016	1.06125998497009
2017	1.06378996372223
2018	1.06187999248505
2019	1.05485999584198
2020	1.04990994930267