Year	Measure
1971	282.96978
1972	278.36934
1973	282.75696
1974	282.20966
1975	281.18684
1976	280.05001
1977	280.25322
1978	274.27156
1979	279.75775
1980	279.09401
1981	269.52677
1982	259.31904
1983	252.21248
1984	257.4665
1985	240.67279
1986	244.24621
1987	252.46624
1988	232.84336
1989	224.44259
1990	223.19766
1991	214.85091
1992	221.55366
1993	214.32913
1994	206.87338
1995	213.2067
1996	212.82033
1997	220.20452
1998	227.04054
1999	233.71128
2000	242.59808
2001	255.73386
2002	253.13496
2003	239.61807
2004	249.75082
2005	248.11857
2006	242.17499
2007	252.89305
2008	256.84104
2009	299.52122
2010	296.62272
2011	305.01244
2012	293.71614
2013	262.86593
2014	272.082