Year	gross (GPI)
1970	0.532329976558685
1971	0.590480029582977
1972	0.571579992771149
1973	0.57753998041153
1974	0.596570014953613
1975	0.637679994106293
1976	0.643760025501251
1977	0.648249983787537
1978	0.660880029201508
1981	0.687780022621155
1982	0.697080016136169
1983	0.73785001039505
1984	0.736530005931854
1988	0.80580997467041
1989	0.822070002555847
1990	0.839049994945526
1991	0.828760027885437
1992	0.832490026950836
1993	0.813499987125397
1994	0.848370015621185
1995	0.856750011444092
1996	0.862969994544983
1999	0.953689992427826
2000	0.968190014362335
2001	0.981660008430481
2002	0.987600028514862
2003	0.986739993095398
2004	0.991750001907349
2005	0.989719986915588
2006	1.00792002677917
2007	1.00611996650696
2008	0.992089986801147
2009	0.993420004844666
2010	1.00634002685547
2011	1.00493001937866
2012	1.02687001228333
2013	0.969980001449585
2014	0.992699980735779
2015	1.00376999378204
2016	1.03070998191833
2017	1.02471005916595
2018	1.02502000331879