Year	% of total
1990	95.61863184926291
1991	95.30931291223965
1992	95.2844731347074
1993	94.8614640963644
1994	94.62432030065531
1995	93.09691962012411
1996	92.16835137451824
1997	92.38222568110822
1998	91.29631150229562
1999	92.24416122798144
2000	91.62244970294095
2001	91.23033399512238
2002	92.0280213771872
2003	92.19085062620603
2004	93.58565529851747
2005	92.67264292507537
2006	92.58393391247807
2007	92.34180176250803
2008	93.1867718536784
2009	91.77907181025726
2010	91.9955359666712
2011	91.39247059615738
2012	91.04727046310427
2013	90.67204031039354
2014	92.44037501652925