Year	%
1971	53.47773
1972	47.91558
1973	48.00298
1974	46.70659
1975	52.86859
1976	51.27958
1977	57.61331
1978	53.85957
1979	56.55534
1980	67.70997
1982	69.50962
1983	58.22702
1989	35.8373
2000	100
2002	78.11265
2010	77.49599
2012	87.34563
2013	86.16496
2014	87.42872
2015	85.17943