Year	gross (GPI)
1971	0.983579993247986
1972	0.988380014896393
1973	0.994859993457794
1974	0.997550010681152
1976	0.9964200258255
1977	0.994470000267029
1978	1.00250005722046
1979	0.991339981555939
1980	0.994579970836639
1981	0.994340002536774
1982	0.9964200258255
1984	1.00739002227783
1985	1.02233004570007
1986	0.997609972953796
1987	0.991249978542328
1988	0.980379998683929
1989	0.97477000951767
1991	0.974089980125427
1992	0.973550021648407
1993	0.981169998645782
1995	0.973999977111816
1996	0.972679972648621
1997	0.971819996833801
1999	0.964850008487701
2000	0.95617002248764
2001	0.971580028533936
2003	0.988940000534058
2005	0.995459973812103
2007	0.984200000762939
2008	0.985719978809357
2009	0.975809991359711
2010	0.970269978046417
2011	0.962289988994598
2012	0.963930010795593