Year	Percent
1975	44.64359
1976	49.41801
1981	87.08282
1982	97.14044
1983	102.03938
1984	129.41551
1986	71.31301
1987	67.78604
1988	61.28763
1989	47.91986
1991	61.66883
1992	55.86912
1993	58.76638
1994	56.28957
1997	57.77214
1998	48.35189
1999	56.13761
2000	48.90006
2001	54.12917
2002	58.47291
2004	58.49093
2005	56.19701
2006	72.8768
2007	83.34066
2009	99.07503
2010	83.69499
2012	73.36997
2013	69.00882