Year	Measure
1971	285.45512
1972	285.17799
1973	291.28925
1974	300.04639
1975	304.69132
1976	299.19665
1977	302.59049
1978	305.46672
1979	312.89634
1980	317.15465
1981	328.86871
1982	336.84875
1983	343.52646
1984	343.35344
1985	349.89265
1986	353.468
1987	376.13064
1988	382.70605
1989	392.22165
1990	398.40548
1991	397.26943
1992	411.93037
1993	421.72901
1994	427.98541
1995	435.87361
1996	447.3937
1997	448.08604
1998	446.82472
1999	460.80496
2000	462.46989
2001	459.79739
2002	455.15081
2003	465.98403
2004	489.37075
2005	497.12043
2006	507.374
2007	523.76346
2008	504.55007
2009	501.69783
2010	498.47695
2011	491.77772
2012	487.0445
2013	488.42696
2014	484.44522