Year	Measure
1971	836.1507
1972	859.8249
1973	877.68226
1974	882.60732
1975	806.84841
1976	866.17805
1977	823.783
1978	802.32012
1979	780.32974
1980	785.1276
1981	770.17613
1982	762.23403
1983	749.74416
1984	734.83049
1985	725.11535
1986	714.60826
1987	708.06436
1988	723.87498
1989	703.07947
1990	678.85166
1991	679.57732
1992	672.49989
1993	656.35607
1994	644.05202
1995	637.84031
1996	615.09368
1997	623.41327
1998	611.63799
1999	595.37337
2000	593.46594
2001	595.72815
2002	599.60151
2003	603.17621
2004	604.17938
2005	607.67003
2006	604.67942
2007	588.60587
2008	592.44272
2009	590.03433
2010	593.75562
2011	608.91171
2012	620.26232
2013	635.32954