Year	%
1971	46.9771
1972	60.85221
1973	54.38473
1974	56.30172
1975	45.29767
1976	52.61691
1977	56.88355
1978	58.55776
1979	66.74226
1980	81.15874
1982	69.68835
1983	55.33372
1984	57.8077
1985	48.52877
1986	59.74196
1989	34.52405
2000	98.96941
2002	78.07313
2010	78.34911
2012	88.69957
2013	85.46746
2014	87.56778
2015	83.75624