Year	Measure
1971	453.93992
1972	457.97127
1973	453.44981
1974	453.75618
1975	448.09715
1976	452.9237
1977	458.05195
1978	454.66921
1979	453.78811
1980	453.28929
1981	448.78322
1982	440.12243
1983	431.29101
1984	439.60155
1985	442.12664
1986	464.58279
1987	466.96678
1988	462.38213
1989	463.32505
1990	457.72523
1991	451.33215
1992	448.65451
1993	445.73648
1994	437.16109
1995	444.68548
1996	447.81097
1997	440.52524
1998	444.46606
1999	441.88982
2000	445.12471
2001	439.02606
2002	432.91362
2003	430.51627
2004	440.43191
2005	443.91592
2006	450.30577
2007	447.63574
2008	450.83157
2009	464.49694
2010	472.05662
2011	468.97558
2012	462.09743
2013	475.8829
2014	513.42649