Year	gross (GPI)
1970	0.167199999094009
1971	0.161200001835823
1972	0.160840004682541
1973	0.168740004301071
1974	0.16695000231266
1975	0.173899993300438
1976	0.180629998445511
1977	0.192279994487762
1978	0.198829993605614
1981	0.242229998111725
1982	0.483579993247986
1984	0.469949990510941
1985	0.476029992103577
1986	0.530939996242523
1988	0.499659985303879
1991	0.537060022354126
1993	0.361770004034042
1994	0.432000011205673
1995	0.474040001630783
2001	0
2003	0.544260025024414
2004	0.40582001209259
2005	0.547689974308014
2006	0.573230028152466
2007	0.567200005054474
2008	0.586019992828369
2009	0.609610021114349
2010	0.625810027122498
2011	0.663450002670288
2012	0.669250011444092
2013	0.655330002307892
2014	0.654020011425018
2015	0.6423299908638
2016	0.645669996738434
2017	0.641690015792847
2018	0.636020004749298