Year	%
1971	59.23693
1974	63.69518
1988	59.85314
1989	62.97189
1990	63.67223
1993	55.44858
1995	62.74632
1998	63.16748
1999	66.04914
2000	62.60067
2001	70.92907
2002	64.7745
2003	76.60852
2004	73.43579
2005	70.35857
2006	75.00565
2007	75.08585
2008	73.29698
2009	72.84588
2010	79.81342
2011	78.50404
2012	72.8611
2013	75.86272
2014	76.03973
2015	73.22756