Year	Percent
1976	4.92821
1977	4.60661
1988	3.90883
1989	4.78873
1990	6.34292
1991	7.10035
1994	8.36233
1995	6.57703
1996	7.16735
1997	7.7044
1999	11.257
2000	12.70033
2001	14.43458
2002	16.52243
2003	20.31883
2004	22.67035
2005	20.37339
2006	20.45049
2009	22.77684
2010	23.22647
2011	26.16082
2012	26.50998
2013	29.44975