Year	gross (GPI)
1972	1.01688003540039
1973	1.02584004402161
1974	1.02892005443573
1976	1.05043005943298
1977	1.04932999610901
1978	1.05188000202179
1979	1.05420005321503
1980	1.05862998962402
1981	1.05711996555328
1982	1.06679999828339
1983	1.06464004516602
1984	1.08516001701355
1985	1.08931994438171
1986	1.08513998985291
1987	1.08585000038147
1988	1.0833899974823
1989	1.0769100189209
1990	1.08712005615234
1991	1.09400999546051
1992	1.10609996318817
1993	1.09168994426727
1994	1.08613002300262
1995	1.07792997360229
1996	1.09221005439758
1997	1.07398998737335
1998	1.05195999145508
1999	1.04770004749298
2000	1.04841995239258
2001	1.05446994304657
2002	1.05659997463226
2003	1.05271005630493
2004	1.02023005485535
2005	1.02005994319916
2006	1.02063000202179
2007	1.02225005626678
2008	1.02240002155304
2009	1.02356994152069
2010	1.02248001098633
2011	1.02109003067017
2012	1.02188003063202
2013	1.05431997776031
2014	1.05675995349884
2015	1.05718004703522
2016	1.05761003494263
2017	1.05625998973846
2018	1.05789995193481
2019	1.05174994468689
2020	1.05539000034332