Year	gross (GPI)
1970	0.728820025920868
1971	0.728359997272491
1972	0.732370018959045
1973	0.734170019626617
1974	0.733269989490509
1975	0.740109980106354
1976	0.748329997062683
1977	0.754700005054474
1978	0.758499979972839
1979	0.767639994621277
1980	0.772029995918274
1981	0.779770016670227
1982	0.785059988498688
1983	0.787660002708435
1984	0.796239972114563
1985	0.806869983673096
1986	0.816020011901855
1987	0.823019981384277
1988	0.831629991531372
1989	0.828760027885437
1990	0.835229992866516
1991	0.849889993667603
1992	0.858680009841919
1993	0.870800018310547
1994	0.87474000453949
1995	0.875649988651276
1996	0.875940024852753
1997	0.884360015392303
1998	0.886590003967285
1999	0.893559992313385
2000	0.897350013256073
2001	0.905359983444214
2002	0.913869976997375
2003	0.956019997596741
2004	0.958949983119965
2005	0.962440013885498
2006	0.967589974403381
2007	0.972239971160889
2008	0.985930025577545
2009	0.991789996623993
2010	0.996469974517822
2011	1.00019001960754
2012	1.00032997131348
2013	1.03032994270325
2014	1.02543997764587
2015	1.02564001083374
2016	1.04220998287201
2017	1.03646004199982
2018	0.988210022449493
2019	0.990989983081818
2020	0.991129994392395