Year	gross (GPI)
1970	0.255670011043549
1971	0.253919988870621
1972	0.247189998626709
1973	0.242320001125336
1974	0.241819992661476
1975	0.248860001564026
1976	0.254619985818863
1977	0.26800999045372
1978	0.271360009908676
1979	0.279659986495972
1980	0.280840009450912
1981	0.286929994821548
1982	0.29381999373436
1983	0.295060008764267
1984	0.300460010766983
1985	0.305240005254745
1986	0.311509996652603
1987	0.333970010280609
1988	0.304230004549026
1989	0.296600013971329
1990	0.322499990463257
1991	0.350919991731644
1992	0.379299998283386
1993	0.404590010643005
1994	0.437429994344711
1995	0.469460010528564
1996	0.502120018005371
1997	0.531970024108887
1998	0.563719987869263
1999	0.59960001707077
2000	0.605409979820251
2001	0.59825998544693
2002	0.595730006694794
2003	0.589489996433258
2004	0.604879975318909
2005	0.610279977321625
2006	0.611720025539398
2007	0.6146399974823
2008	0.611310005187988
2009	0.625549972057343
2010	0.624210000038147
2011	0.608259975910187
2012	0.614220023155212
2013	0.623340010643005
2014	0.625329971313477
2015	0.642880022525787
2016	0.64954000711441
2017	0.64750999212265
2018	0.664250016212463
2019	0.685850024223328
2020	0.698249995708466