Year	gross (GPI)
1981	1.2762199640274
1982	1.27458000183105
1983	1.28435003757477
1984	1.32020998001099
1985	1.3303200006485
1986	1.39328002929688
1987	1.45834004878998
1988	1.40381002426147
1989	1.40778005123138
1990	1.28252995014191
1991	1.20536005496979
1992	1.13822996616364
1997	1.33120000362396
1998	1.31123995780945
1999	1.38205003738403
2000	1.44356000423431
2001	1.40234994888306
2002	1.39627003669739
2003	1.40116000175476
2004	1.41507995128632
2005	1.44059002399445
2006	1.44510996341705
2007	1.46051001548767
2008	1.47449004650116
2009	1.456169962883
2010	1.42969000339508
2011	1.38943004608154
2012	1.35783994197845
2013	1.34127998352051
2014	1.29967999458313
2015	1.35910999774933
2016	1.34677004814148
2017	1.31445002555847
2018	1.32555997371674
2019	1.28015995025635
2020	1.26305997371674
2021	1.27304995059967
2022	1.30770003795624