Year	gross (GPI)
1971	0.668730020523071
1972	0.538720011711121
1973	0.480379998683929
1974	0.562770009040833
1975	0.5730299949646
1977	0.695590019226074
1979	0.819480001926422
1980	0.887589991092682
1981	0.962140023708344
1982	1.09074997901917
1983	1.1188999414444
1984	1.13517999649048
1985	1.17294001579285
1986	1.18642997741699
1987	1.2279200553894
1988	1.24336004257202
1989	1.28764998912811
1990	1.30165004730225
1991	1.29779005050659
1992	1.31867003440857
1993	1.30560994148254
1994	1.279629945755
1995	1.32144999504089
1996	1.35672998428345
1997	1.37163996696472
1998	1.38613998889923
1999	1.16908001899719
2000	1.18127000331879
2001	1.13697004318237
2002	1.21071994304657
2003	1.26398003101349
2004	1.42856001853943
2005	1.4234299659729
2006	1.39028000831604
2007	1.45911002159119
2008	1.40688002109528
2009	1.40551996231079
2010	1.39952003955841
2011	1.39777004718781
2012	1.35446000099182
2013	1.40146005153656
2015	1.28460001945496
2016	1.28312003612518
2017	1.40463995933533
2018	1.36904001235962
2019	1.39846003055573
2020	1.45397996902466
2021	1.4617999792099