1952   400.4486107
1957   575.9870009
1962   487.6740183
1967   612.7056934
1972   676.9000921
1977   741.2374699
1982   962.4213805
1987  1378.904018
1992  1655.784158
1997  2289.234136
2002  3119.280896
2007  4959.114854