Year	gross (GPI)
1971	1.22897005081177
1972	1.245609998703
1973	1.32412004470825
1974	1.24103999137878
1975	1.29047000408173
1976	1.23626005649567
1977	1.09740996360779
1978	1.12943005561829
1979	1.11626005172729
1986	1.23424005508423
1987	1.26164996623993
1988	1.30401003360748
1989	1.24958002567291
1990	1.2815500497818
1991	1.18737995624542
1992	1.19861996173859
1993	1.19736003875732
2001	1.18238997459412
2002	1.40934002399445
2005	1.3388500213623
2006	1.36536002159119
2007	1.37413001060486
2008	1.31358003616333
2009	1.25418996810913
2010	1.28961002826691
2011	1.35857999324799
2012	1.3583300113678
2013	1.35335004329681
2014	1.37687003612518
2015	1.32175004482269
2021	1.21747994422913