Year	gross (GPI)
1973	1.11073994636536
1974	1.10933995246887
1975	1.18265998363495
1976	1.17242002487183
1977	1.11369001865387
1979	1.11125004291534
1980	1.13506996631622
1981	1.14629995822906
1983	1.10881996154785
1984	1.09598994255066
1985	1.0944299697876
1986	1.1313099861145
1987	1.07416999340057
1988	1.07845997810364
1989	1.10871005058289
1991	1.07513999938965
1993	1.06111001968384
1999	1.01514995098114
2000	1.02751994132996
2001	1.02620995044708
2002	1.03589999675751
2003	1.03939998149872
2004	1.04453003406525
2005	1.06130003929138
2007	1.06650996208191