Year	%
1976	10.06413
1977	12.95896
1978	16.12005
1979	14.32153
1980	14.43204
1981	17.01511
1982	10.95253
1983	11.1736
1984	11.70259
1985	12.49287
1986	13.90135
1987	17.89842
1988	17.46511
1989	11.11557
1991	15.63209
1992	17.17991
2003	60.77014
2004	58.17566
2007	66.17432
2008	62.70992
2009	69.99116
2010	71.25481
2011	69.33454
2012	75.66893
2013	77.23248
2014	79.60397
2015	86.76805
2016	76.30755
2017	76.29475