Year	% of total
1990	88.87473701838067
1991	88.88413061676117
1992	89.14241029645571
1993	89.21241599928422
1994	89.1798898925433
1995	88.50954681255587
1996	87.97684662143928
1997	87.52945305960377
1998	87.10397441833418
1999	86.5602292655174
2000	85.48044396588399
2001	85.37343703610581
2002	85.11193847820428
2003	85.09357747398317
2004	85.09375882864433
2005	85.21820368732753
2006	85.00375933038548
2007	84.9350313666066
2008	84.69593659794737