Year	Percent
1977	11.89915
1978	14.26358
1979	12.50877
1980	9.99622
1981	11.76853
1982	11.02428
1983	10.38345
1984	12.14937
1985	12.17159
1986	12.37772
1987	11.32141
1988	13.68791
1989	13.02866
1990	14.16971
1991	12.47311
1992	13.2262
1993	9.78746
1994	7.06992
1995	9.1981
1996	8.15513
1997	6.44849
1998	7.0581
1999	6.93973
2000	8.4664
2001	6.84748
2002	6.98621
2003	6.10488
2004	5.85289
2005	6.59731
2006	6.14814
2007	5.95899
2008	6.03591
2009	6.34514
2010	6.26507
2011	6.33056
2012	6.15236
2013	6.54391
2014	6.55415
2015	6.2603
2016	6.75105
2017	6.76906
2018	7.10938
2019	7.00102
2020	8.59755
2021	5.35669
2022	4.66751