Year	gross (GPI)
1970	1.0131299495697
1971	1.00330996513367
1972	1.00110995769501
1973	1.00642001628876
1974	1.01049995422363
1975	1.00713002681732
1976	1.01582002639771
1977	1.00828003883362
1978	1.00572001934052
1979	1.0081000328064
1980	1.00551998615265
1981	1.01147997379303
1982	0.98989999294281
1983	0.995890021324158
1984	0.993579983711243
1985	0.997489988803864
1986	0.995819985866547
1989	1.00384998321533
1990	1.00768005847931
1991	0.994270026683807
1992	0.998130023479462
1993	1.00756001472473
1998	0.999539971351624
1999	0.999559998512268
2000	0.995980024337769
2002	0.994989991188049
2003	0.992900013923645
2004	0.982309997081757
2005	0.983070015907288
2006	0.986660003662109
2007	0.986729979515076
2008	0.985719978809357
2009	0.988659977912903
2010	1.00042998790741
2011	0.99864000082016
2012	1.00057995319366
2013	0.9896399974823
2014	0.989369988441467
2015	0.988600015640259
2016	0.988529980182648
2017	0.987600028514862
2018	0.98565000295639
2019	0.982060015201569
2020	0.979330003261566