Year	gross (GPI)
1971	0.927100002765656
1974	1.24354994297028
1975	0.960060000419617
1976	0.939509987831116
1977	1.02327001094818
1978	0.907899975776672
1979	0.966880023479462
1984	0.858539998531342
1992	0.952229976654053
2007	0.964619994163513
2008	0.946770012378693
2009	0.950380027294159
2010	0.91541999578476
2011	0.928139984607697
2012	0.95210999250412
2013	0.962451756000519
2014	0.949919998645782
2015	0.966189980506897
2017	0.984059989452362
2018	0.992079973220825
2019	0.977081418037415