Year	Measure
1971	1951.77748
1972	1963.73634
1973	2087.44734
1974	2282.55217
1975	2626.21791
1976	3171.78381
1977	3661.25175
1978	3746.83513
1979	4299.9084
1980	4612.54613
1981	4848.71164
1982	5205.33748
1983	5589.55137
1984	15305.95958
1985	15926.37627
1986	16450.51006
1987	14702.44313
1988	15363.21856
1989	15402.52344
1990	15621.12471
1991	14214.39291
1992	18497.87894
1993	21644.38385
1994	20477.15743
1995	20553.52236
1996	20597.30277
1997	21105.00395
1998	21251.35652
1999	20637.97532
2000	20014.62503
2001	20130.48546
2002	20016.37765
2003	19774.98713
2004	18982.99448
2005	21325.55378
2006	21508.45042
2007	20592.90022
2008	18492.00154
2009	17460.33219
2010	18038.26695
2011	17910.9405
2012	17845.48272
2013	18687.69533
2014	19592.23195