Year	gross (GPI)
1971	0.586399972438812
1972	0.637099981307983
1973	0.656409978866577
1974	0.687219977378845
1975	0.723169982433319
1976	0.747009992599487
1977	0.779500007629395
1978	0.808960020542145
1979	0.857599973678589
1980	0.9064000248909
1981	0.926129996776581
1982	0.976890027523041
1983	0.997910022735596
1984	1.02258002758026
1985	1.04009997844696
1986	1.07523000240326
1987	1.0639899969101
1988	1.0718400478363
1989	1.04745995998383
1990	1.02906000614166
1991	1.02577996253967
1992	1.07128000259399
1993	1.08080995082855
1994	1.07082998752594
1996	1.04077005386353
1999	1.04454004764557
2000	1.04602003097534
2002	1.04033005237579
2003	1.03784000873566
2004	1.02838003635406
2005	1.02969002723694
2006	1.03521001338959
2007	1.03360998630524
2008	1.03242003917694
2010	1.03886997699738
2011	1.03715002536774
2012	1.02777004241943
2013	1.02233004570007
2014	1.03500998020172
2017	1.03153002262115
2018	1.03314995765686
2019	1.02483999729156
2020	1.03022003173828
2021	1.02014994621277