Year	gross (GPI)
1971	0.979889988899231
1972	1.041139960289
1973	0.950540006160736
1974	0.927839994430542
1990	0.96382999420166
1991	0.968940019607544
1992	0.971409976482391
1993	0.969250023365021
1999	0.953390002250671
2000	0.958450019359589
2001	0.964359998703003
2002	0.946829974651337
2003	0.935769975185394
2004	0.932940006256104
2005	0.939899981021881
2006	0.962350010871887
2007	0.94990998506546
2008	0.95780998468399
2009	0.966489970684052
2010	0.981369972229004
2011	0.986869990825653
2012	0.982330024242401
2013	0.98650997877121
2014	0.991729974746704
2015	0.984139978885651
2016	0.986140012741089
2017	0.988139986991882
2018	0.99345999956131
2019	0.979939997196198
2020	0.975019991397858
2021	0.978659987449646