Year	%
1977	84.53858
1978	85.02948
1980	55.65227
1985	51.269
1986	47.67249
1987	45.26459
1988	38.88801
1990	45.23842
1991	49.62107
1992	50.9585
1993	50.59548
1994	53.73392
1998	54.60742
2001	51.67192
2004	54.30838
2005	58.70544
2006	60.79059
2008	39.30534
2011	57.504
2013	58.19251
2014	59.21408
2016	58.3211
2017	65.559