Year	%
1971	59.35835
1974	65.25025
1988	65.44645
1989	65.41593
1990	64.81763
1993	54.99345
1995	60.23107
1998	64.04481
1999	67.59022
2000	63.49719
2001	71.45363
2002	66.20656
2003	77.48665
2004	75.41173
2005	71.53178
2006	75.95101
2007	76.32701
2008	74.65815
2009	74.06324
2010	80.96271
2011	79.15484
2012	73.00607
2013	76.10707
2014	76.42909
2015	73.86503