Year	gross (GPI)
1970	0.689059972763062
1971	0.687129974365234
1972	0.684650003910065
1973	0.689660012722015
1974	0.689360022544861
1975	0.679409980773926
1976	0.671800017356873
1977	0.664889991283417
1978	0.663940012454987
1979	0.653710007667542
1980	0.644460022449493
1981	0.648479998111725
1982	0.654529988765717
1983	0.616400003433228
1984	0.594489991664886
1985	0.650789976119995
1986	0.713240027427673
1987	0.734860002994537
1988	0.739650011062622
1989	0.74753999710083
1990	0.760280013084412
1991	0.770039975643158
1992	0.779540002346039
1993	0.784959971904755
1994	0.786740005016327
1995	0.805180013179779
1996	0.812269985675812
1997	0.815760016441345
1998	0.815760016441345
1999	0.817110002040863
2000	0.802119970321655
2001	0.796679973602295
2002	0.777010023593903
2003	0.783599972724915
2004	0.780939996242523
2005	0.787750005722046
2006	0.786090016365051
2007	0.777700006961823
2008	0.796999990940094
2009	0.809840023517609
2010	0.821410000324249
2011	0.828069984912872
2012	0.847739994525909
2013	0.8612300157547
2014	0.862219989299774
2015	0.867760002613068
2016	0.874559998512268
2017	0.884819984436035
2018	0.892790019512177
2019	0.893980026245117
2020	0.900269985198975