Year	gross (GPI)
1971	0.330900013446808
1972	0.330040007829666
1973	0.34893000125885
1974	0.336750000715256
1975	0.359200000762939
1976	0.354930013418198
1977	0.36395999789238
1985	0.379559993743896
1986	0.396450012922287
1987	0.396750003099442
1988	0.403990000486374
1989	0.424160003662109
1990	0.44242998957634
1991	0.45388999581337
1992	0.476319998502731
1993	0.477510005235672
1994	0.482479989528656
1995	0.486119985580444
1996	0.495519995689392
1997	0.52658998966217
1998	0.552779972553253
1999	0.58704000711441
2000	0.613699972629547
2001	0.638260006904602
2002	0.649129986763
2003	0.665059983730316
2004	0.658670008182526
2005	0.677250027656555
2006	0.680419981479645
2007	0.698790013790131
2008	0.704469978809357
2009	0.706709980964661
2010	0.730159997940063
2011	0.74617999792099
2012	0.753260016441345
2013	0.75789999961853
2014	0.754000008106232
2015	0.766359984874725
2016	0.768679976463318
2017	0.757109999656677
2018	0.777830004692078
2019	0.778240025043488
2021	0.80009001493454