Year	gross (GPI)
1970	0.861469984054565
1971	0.84103000164032
1972	0.844630002975464
1973	0.82956999540329
1974	0.809979975223541
1975	0.857089996337891
1976	0.88112998008728
1977	0.880270004272461
1978	0.879279971122742
1981	0.876919984817505
1982	0.900569975376129
1983	0.944069981575012
1984	0.948339998722076
1985	0.95210999250412
1986	0.943490028381348
1987	0.953149974346161
1988	0.952530026435852
1989	0.96671998500824
1990	0.968940019607544
1991	0.984059989452362
1992	0.992720007896423
1993	0.975639998912811
1994	0.970740020275116
1995	0.965789973735809
1996	0.964869976043701
1997	0.964359998703003
1998	0.943729996681213
1999	0.971140027046204
2000	0.971920013427734
2001	0.977020025253296
2002	0.978359997272491
2003	0.982299983501434
2004	0.985790014266968
2005	0.969319999217987
2006	0.969669997692108
2007	0.963599979877472
2008	0.981230020523071
2009	0.97775000333786
2010	1.03270995616913
2011	1.03632998466492
2012	0.997099995613098
2013	0.996599972248077
2014	0.975399971008301
2015	0.971930027008057
2016	0.969150006771088
2017	0.968689978122711
2018	0.967230021953583