Year	gross (GPI)
1971	0.0812299996614456
1972	0.098130002617836
1973	0.12347000092268
1974	0.124820001423359
1975	0.154909998178482
2002	0.633899986743927
2003	0.634029984474182
2004	0.634130001068115
2005	0.653540015220642
2006	0.717859983444214
2007	0.782140016555786
2008	0.788240015506744
2009	0.783930003643036
2010	0.808000028133392
2011	0.730139970779419
2012	0.767780005931854
2013	0.768830001354218
2014	0.774119973182678
2015	0.797559976577759
2016	0.874870002269745
2017	0.807439982891083
2018	0.87966001033783