Year	gross (GPI)
1970	1.0202499628067
1971	1.02346003055573
1972	1.02968001365662
1973	1.03603005409241
1975	1.0689400434494
1977	1.04401004314423
1979	1.0905100107193
1980	1.08767998218536
1982	1.08580005168915
1983	1.09626996517181
1984	1.12024998664856
1985	1.24346005916595
1986	1.21280002593994
1987	1.20956003665924
1988	1.22054004669189
1989	1.19895005226135
1998	1.07799005508423
1999	1.06695997714996
2000	1.06800997257233
2001	1.06700003147125
2002	1.05313003063202
2004	1.04005002975464
2005	1.03825998306274
2006	1.0378999710083
2007	1.04186999797821
2008	1.04219996929169
2010	1.03515994548798