Year	gross (GPI)
1971	0.999000012874603
1972	1.00100994110107
1974	0.97477000951767
1975	0.988610029220581
1976	0.96492999792099
1982	0.962339997291565
1984	0.943690001964569
1986	0.96314001083374
1987	0.979149997234344
1991	0.985490024089813
1994	0.955429971218109
1998	0.918420016765594
1999	0.920220017433167
2000	0.945760011672974
2001	0.952499985694885
2002	0.955269992351532
2003	0.965719997882843
2004	0.954779982566834
2005	0.904569983482361
2007	0.958739995956421
2008	0.932569980621338
2009	0.95304000377655
2010	0.949169993400574
2011	0.984619975090027
2012	0.97393000125885
2013	0.961700022220612
2014	0.984149992465973
2015	0.990729987621307
2016	0.989359974861145
2017	0.98470002412796
2018	0.988439977169037
2019	0.966477394104004
2020	0.979326725006104