Year	Percent
1960	4.74008
1961	7.65951
1962	9.86948
1963	8.42956
1964	13.27485
1965	13.03038
1966	10.32699
1967	9.51282
1968	8.53752
1969	8.09482
1970	5.96789
1971	5.40168
1972	5.74151
1973	4.42699
1974	3.57711
1975	4.75784
1976	2.35783
1977	2.24496
1978	4.31168
1979	2.96314
1980	1.92376
1981	4.0638
1982	9.90251
1983	29.49491
1984	24.01106
1985	24.8135
1986	16.3041
1987	18.26007
1988	16.1369
1989	16.14068
1990	14.25739
1991	13.89693
1992	9.09462
1993	5.81243
1994	4.06485
1995	2.03697
1996	-0.01013
1997	0.14823
1998	0.96031
1999	0.11481
2000	0.81975
2001	0.44404
2002	0.40159
2003	1.22146
2004	0.7312
2005	0.85804
2006	0.66517
2007	1.02882
2008	1.01747
2009	1.98485
2010	1.35396
2011	0.41467
2012	0.30349
2013	0.32882
2014	0.54554
2015	1.04591
2016	0.90612
2017	0.90796
2018	0.86713
2019	0.53991
2020	2.06603
2021	0.64511