Year	gross (GPI)
1971	0.979439973831177
1972	0.963429987430573
1973	0.994530022144318
1974	1.00338995456696
1975	1.0025999546051
1976	1.09396994113922
1977	1.08107995986938
1978	1.09052002429962
1979	1.08104002475739
1980	1.10844004154205
1981	1.11111998558044
1982	1.13567996025085
1983	1.13074004650116
1984	1.1329300403595
1985	1.12595999240875
1987	1.03833997249603
1988	1.02562999725342
1989	1.03899002075195
1990	1.04541003704071
1991	1.04609000682831
1992	1.04351997375488
1993	1.13849997520447
1994	1.1319500207901
1995	1.15086996555328
1996	1.17372000217438
1997	1.1938099861145
1998	1.25336003303528
1999	1.26194000244141
2000	1.27014994621277
2001	1.26311004161835
2002	1.21399998664856
2003	1.18289005756378
2004	1.03179001808167
2005	0.995519995689392
2006	0.995389997959137
2007	0.99278998374939
2008	0.993579983711243
2009	0.992129981517792
2010	0.989669978618622
2011	0.989820003509521
2012	0.986869990825653
2013	1.13380002975464
2014	1.13521003723145
2015	1.14045000076294
2016	1.11816000938416
2017	1.06608998775482
2018	1.06579005718231
2019	1.06784999370575
2020	1.08490002155304