Year	gross (GPI)
1971	0.747160017490387
1972	0.74099999666214
1973	0.77920001745224
1974	0.81647002696991
1975	0.8369500041008
1976	0.855610013008118
1977	0.884760022163391
1978	0.921720027923584
1979	0.921639978885651
1980	0.963800013065338
1981	0.933369994163513
1982	0.917859971523285
1983	0.904640018939972
1984	0.878920018672943
1985	0.905910015106201
1986	0.909940004348755
1987	0.924759984016418
1988	0.97969001531601
1989	0.984250009059906
1990	1.00247001647949
1996	1.04320001602173
1998	1.01256000995636
1999	0.984019994735718
2000	0.967379987239838
2001	0.974240005016327
2002	0.997850000858307
2003	0.989859998226166
2004	0.981360018253326
2005	0.977090001106262
2006	1.03115999698639
2007	1.03032994270325
2008	1.03522002696991
2009	1.04300999641418
2010	1.04635000228882
2011	1.04673004150391
2012	1.04814994335175
2013	1.02850997447968
2014	1.01839995384216
2015	1.04367005825043
2016	1.04683005809784
2017	1.07121002674103
2018	1.05664002895355
2019	1.02386999130249
2021	1.04857003688812