Year	Percent
1960	2.74826
1961	2.83569
1962	2.86663
1963	2.80904
1964	2.64665
1965	2.41962
1966	2.18024
1967	1.96666
1968	1.77687
1969	1.62816
1970	2.19889
1971	2.90119
1972	2.78588
1973	2.68779
1974	2.37009
1975	2.07371
1976	2.03594
1977	2.00269
1978	1.98179
1979	1.90382
1980	1.82257
1981	1.81718
1982	1.81974
1983	1.82964
1984	1.92267
1985	2.01926
1986	2.04002
1987	2.0484
1988	2.04494
1989	1.58479
1990	-0.12186
1991	0.97767
1992	0.93519
1993	0.93779
1994	0.76506
1995	0.56154
1996	0.41427
1997	0.36941
1998	0.34642
1999	0.69608
2000	1.21344
2001	1.16516
2002	1.13312
2003	1.14502
2004	1.2613
2005	1.40476
2006	1.47963
2007	1.51533
2008	2.47801
2009	2.45287
2010	1.59506
2011	1.73459
2012	1.78635
2013	1.77852
2014	1.7585
2015	1.72631
2016	1.6774
2017	1.64995