Year	gross (GPI)
1971	0.171220004558563
1972	0.113080002367496
1973	0.150460004806519
1974	0.200049996376038
1975	0.247830003499985
1976	0.239089995622635
1977	0.259930014610291
1978	0.264719992876053
1979	0.245480000972748
1980	0.281120002269745
1981	0.269050002098083
1982	0.267930001020432
1983	0.282750010490417
1984	0.282420009374619
1985	0.294779986143112
1986	0.298700004816055
1987	0.312599986791611
1988	0.314310014247894
1989	0.313329994678497
1990	0.294470012187958
1991	0.29653999209404
1992	0.286410003900528
1993	0.290769994258881
1994	0.313019990921021
1995	0.27853000164032
1996	0.312799990177155
1997	0.289180010557175
1999	0.293379992246628
2002	0.344419986009598
2003	0.293660014867783
2005	0.454750001430511
2006	0.461459994316101
2007	0.459100008010864
2008	0.496349990367889
2009	0.482899993658066
2010	0.476009994745255
2011	0.491470009088516
2012	0.489969998598099
2013	0.486699998378754
2014	0.479420006275177
2015	0.515519976615906
2016	0.504980027675629
2017	0.514310002326965
2018	0.574620008468628
2019	0.554629981517792
2020	0.546069979667664
2021	0.589250028133392
2022	0.624419987201691