Year	gross (GPI)
1970	0.806020021438599
1971	0.800249993801117
1972	0.79926997423172
1973	0.786870002746582
1974	0.772750020027161
1975	0.816940009593964
1976	0.83704000711441
1977	0.837080001831055
1978	0.839699983596802
1981	0.839999973773956
1982	0.858730018138886
1983	0.897849977016449
1984	0.900730013847351
1988	0.908429980278015
1989	0.922969996929169
1990	0.930589973926544
1991	0.938650012016296
1992	0.945789992809296
1993	0.928030014038086
1994	0.934509992599487
1995	0.93189001083374
1996	0.93163001537323
1999	0.964850008487701
2000	0.970269978046417
2001	0.978320002555847
2002	0.980740010738373
2003	0.982840001583099
2004	0.986850023269653
2005	0.975489974021912
2006	0.982860028743744
2007	0.978890001773834
2008	0.984170019626617
2009	0.9826700091362
2010	1.02081000804901
2011	1.02225995063782
2012	1.00821995735168
2013	0.984489977359772
2014	0.982280015945435
2015	0.985639989376068
2016	0.995899975299835
2017	0.993650019168854
2018	0.993399977684021