Year	Percent
1971	15.67814
1972	21.29663
1973	23.91201
1974	33.30822
1975	16.45625
1976	16.3355
1977	10.86538
1978	11.15195
1979	11.17807
1980	8.36875
1981	4.81604
1982	4.34833
1983	2.87829
1984	1.91057
1985	2.15055
1986	2.71411
1987	3.57567
1988	3.96023
1989	3.46727
1990	9.34023
1991	14.88283
1992	16.83096
1993	17.77045
1994	20.10398
1995	16.2855
1996	16.72936
1997	17.85884
1998	19.60417
1999	25.55903
2000	24.13114
2001	45.8663
2002	57.31095
2003	77.16918
2004	97.82458
2005	101.82785
2006	115.8601
2007	119.50924
2008	108.41135
2009	95.54412
2010	87.8832
2011	68.23364
2012	51.39656
2013	48.52114
2014	47.9485
2015	53.51238
2016	54.24087