Year	gross (GPI)
1970	0.84060001373291
1971	0.901639997959137
1972	0.91473001241684
1973	0.911490023136139
1974	0.898429989814758
1975	0.905279994010925
1976	0.898649990558624
1977	0.898239970207214
1978	0.910860002040863
1979	0.910669982433319
1980	0.942089974880219
1981	0.940419971942902
1989	0.944480001926422
1990	0.976109981536865
1991	0.956520020961761
1992	0.956369996070862
1993	0.967100024223328
1994	0.968869984149933
1997	0.975780010223389
1998	0.980970025062561
1999	0.976880013942719
2000	0.973909974098206
2001	0.985450029373169
2002	0.991850018501282
2003	0.99278998374939
2004	0.980319976806641
2005	0.974590003490448
2006	0.984070003032684
2007	0.977249979972839
2008	1.00014996528625
2009	0.987879991531372
2010	0.990580022335052
2011	0.968976736068726
2012	0.97421658039093
2013	0.967509984970093
2015	0.973699986934662
2016	0.962795615196228
2017	0.947157263755798
2018	0.945716440677643
2019	0.958119988441467
2020	0.976840019226074