Year	Measure
1971	496.45388
1972	492.89289
1973	496.88615
1974	489.74619
1975	488.36046
1976	492.72905
1977	505.59601
1978	502.83045
1979	504.00809
1980	508.52544
1981	490.31147
1982	514.75622
1983	489.6423
1984	485.84498
1985	467.43907
1986	465.62005
1987	476.66456
1988	485.02308
1989	490.6302
1990	480.20535
1991	470.67295
1992	477.04692
1993	473.93488
1994	478.36078
1995	494.65104
1996	483.20552
1997	513.73024
1998	537.0386
1999	459.8945
2000	458.43597
2001	481.93629
2002	489.00397
2003	518.66091
2004	545.82294
2005	557.40341
2006	529.55762
2007	608.4232
2008	590.82993
2009	554.67945
2010	556.94688
2011	605.89983
2012	602.48722
2013	600.5573
2014	607.86465