Year	Ratio
1933	1085
1934	974.1
1935	955.7
1936	1008
1937	901.7
1938	854.8
1939	834.1
1940	765.9
1946	668.1
1947	700.1
1948	583
1949	533.7
1950	533.9
1951	569.8
1952	520
1953	471.6
1954	475.9
1955	418
1956	396.2
1957	282.2
1958	277.3
1959	209.6
1960	242.3
1961	200.3
1962	230
1963	223.4
1964	206.5
1965	203.6
1966	180.1
1967	168.2
1968	169.2
1969	157.6
1970	143.3
1971	126.4
1972	112
1973	102.7
1974	94.8
1975	85.7
1976	79.9
1977	80.2
1978	77.2
1979	77.2
1980	137.1
1990	56
1995	45
2000	40
2005	36
2010	31
2013	29