Year	gross (GPI)
1971	1.06988000869751
1972	1.05541002750397
1973	1.02892005443573
1974	1.03277003765106
1975	1.01986002922058
1976	1.01155996322632
1977	1.01513004302979
1978	1.02014994621277
1979	0.984629988670349
1980	0.980350017547607
2001	1.03913998603821
2002	1.06155002117157
2003	1.08097994327545
2004	1.11161005496979
2005	1.09012997150421
2006	1.08261001110077
2011	1.07334005832672
2012	1.06055998802185
2013	1.06640994548798
2014	1.05304002761841
2015	1.04849994182587