Year	Percent
1960	7.05905
1961	7.27941
1962	3.86876
1963	9.03645
1964	6.38541
1965	7.73576
1966	6.82474
1967	5.76897
1968	6.00053
1969	6.6204
1970	7.02944
1971	6.41331
1972	7.25918
1973	8.27168
1974	8.01312
1975	7.53857
1976	7.03571
1977	7.25237
1978	6.67558
1979	7.1239
1980	9.05273
1981	9.42035
1982	7.60968
1983	11.42182
1984	13.54758
1985	12.24796
1986	8.81659
1987	9.45994
1988	10.88822
1989	8.92961
1990	8.19999
1991	8.67697
1992	10.86825
1993	10.50327
1994	9.66505
1995	7.52888
1996	6.73021
1997	6.98365
1998	7.0305
1999	9.5649
2000	10.18805
2001	12.37171
2002	14.23059
2003	15.18078
2004	16.54576
2005	15.24383
2006	14.37432
2007	13.32768
2008	13.534
2009	10.85137
2010	10.7382
2011	11.46614
2012	11.70305
2013	11.63018
2014	11.01194
2015	12.90019
2016	12.49462
2017	12.56757