Year	gross (GPI)
1971	1.16249001026154
1972	0.996119976043701
1973	1.15068995952606
1974	1.15160000324249
1975	1.15313994884491
1976	1.10771000385284
1977	1.10055994987488
1978	1.09112000465393
1979	1.01217997074127
1980	1.00753998756409
2001	1.06786000728607
2002	1.08465003967285
2003	1.13033998012543
2004	1.16120994091034
2005	1.13101994991302
2006	1.08771002292633
2010	1.17603003978729
2011	1.17317998409271
2012	1.1630699634552
2013	1.16894996166229
2014	1.14358997344971
2015	1.12169003486633