Year	%
1976	9.41679
1977	9.63158
1978	12.89753
1979	7.78302
1980	7.97887
1981	15.62199
1982	7.45036
1983	8.67815
1984	9.33134
1985	10.78176
1986	13.60038
1987	18.02177
1988	15.94858
1989	10.29148
1991	13.1963
1992	16.25158
2003	63.82248
2004	55.49483
2007	63.39477
2008	64.38854
2009	63.43387
2010	66.65397
2011	66.33929
2012	72.56525
2013	74.84095
2014	77.63964
2015	85.63046
2016	76.95371
2017	76.97064