Year	gross (GPI)
1979	1.10564005374908
1980	0.913429975509644
1981	1.07974004745483
2006	1.53419995307922
2007	1.5786600112915
2008	1.49624001979828
2009	1.58861994743347
2010	1.49958002567291
2011	1.501620054245
2012	1.47901999950409
2013	1.53560996055603
2014	1.45164000988007
2015	1.55287003517151
2017	1.38882994651794
2018	1.28531002998352
2023	1.32552003860474