Year	Percent
1960	1.13923
1961	1.66176
1962	2.07205
1963	2.29596
1964	2.40956
1965	2.27993
1966	2.169
1967	2.08984
1968	1.89551
1969	1.66512
1970	1.41401
1971	1.07612
1972	0.81073
1973	0.59608
1974	0.50762
1975	0.51182
1976	0.55293
1977	0.53652
1978	0.4904
1979	0.42507
1980	0.31431
1981	0.2046
1982	0.15482
1983	0.00658
1984	-0.19108
1985	-0.38988
1986	-0.6743
1987	-0.87033
1988	-0.92886
1989	-0.70491
1990	-0.33547
1991	0.16445
1992	0.57005
1993	0.8271
1994	0.91402
1995	0.83942
1996	0.77649
1997	0.69536
1998	0.67432
1999	0.61497
2000	0.608
2001	0.62027
2002	0.54039
2003	0.5564
2004	0.55332
2005	0.5908
2006	0.65548
2007	0.66044
2008	0.68055
2009	0.68201
2010	0.70452
2011	0.64871
2012	0.65048
2013	0.61672
2014	0.61
2015	0.55665
2016	0.52451
2017	0.47261