Year	% of total
1990	86.52900396691787
1991	86.41662108472251
1992	86.70602450016254
1993	86.61147950873017
1994	83.09381833832762
1995	83.09343112436807
1996	82.77887562014772
1997	82.09298677039028
1998	81.80952174803161
1999	81.51129165133833
2000	80.62873954426254
2001	80.54548499725523
2002	80.53370138602442
2003	80.47705181724442
2004	80.36967201004597
2005	80.33878752863053
2006	79.81485763505889
2007	79.93708291542676
2008	79.547576963055