Year	gross (GPI)
1971	0.716220021247864
1998	0.939350008964539
1999	0.93953001499176
2000	0.93011999130249
2001	0.93452000617981
2002	0.938979983329773
2003	0.939480006694794
2004	0.944090008735657
2005	0.954240024089813
2006	0.964860022068024
2007	0.975300014019012
2008	0.984390020370483
2009	0.99602997303009
2010	0.995840013027191
2011	1.0037100315094
2012	0.996919989585876
2013	0.994740009307861
2014	0.991590023040771
2015	0.985319972038269
2016	0.980549991130829
2017	0.97886997461319
2018	0.9791100025177
2019	0.982119977474213
2020	0.989610016345978