Year	gross (GPI)
1970	1.00952005386353
1971	1.01225996017456
1972	1.01515996456146
1973	1.01691997051239
1974	1.02319002151489
1975	1.02138996124268
1976	1.02517998218536
1977	1.02497005462646
1978	1.0286500453949
1979	1.02819001674652
1980	1.02392995357513
1981	1.02461004257202
1982	1.0188000202179
1983	1.05201995372772
1984	1.00394999980927
1985	1.01575994491577
1986	1.0171400308609
1987	1.00511002540588
1988	1.00587999820709
1989	1.00713002681732
1991	1.06523001194
1992	1.09596002101898
1993	1.06563997268677
1995	1.04982995986938
1996	1.01488995552063
1998	1.02708995342255
1999	1.04314994812012
2000	1.03857004642487
2002	1.03801000118256
2004	1.04039001464844
2005	1.03676998615265
2006	1.04431998729706
2007	1.04789996147156
2008	1.04508996009827
2009	1.04764997959137
2010	1.03966999053955
2011	1.02827000617981
2012	1.02807998657227
2013	1.02833998203278
2014	1.02436995506287
2015	1.0215699672699
2016	1.01984000205994
2017	1.0140700340271
2018	1.01321005821228
2019	1.01104998588562
2020	1.00679004192352