Year	gross (GPI)
1971	1.03163003921509
1972	1.03114998340607
1973	1.03570997714996
1974	1.04367995262146
1975	1.04354000091553
1984	1.06150996685028
1985	1.06050002574921
1986	1.05637001991272
1987	1.05682003498077
1988	1.05745005607605
1989	1.06088995933533
1991	1.05207002162933
1992	1.04656994342804
1993	1.04727005958557
1999	1.0513299703598
2000	1.04688000679016
2001	1.04188001155853
2002	1.03903996944427
2003	1.036749958992
2004	1.03452003002167
2005	1.03371000289917
2006	1.03102004528046
2007	1.02628004550934
2008	1.02226996421814
2009	1.01911997795105
2010	1.01933002471924
2011	1.02064001560211
2012	1.02439999580383
2013	1.02929997444153
2014	1.02149999141693
2015	1.01830005645752
2016	1.01838004589081
2017	1.01935994625092