Year	% of total
1990	89.30868641777185
1991	89.18315631673984
1992	89.26123563914611
1993	89.20599060267025
1994	80.43024891415176
1995	80.21298687068266
1996	79.72548079386347
1997	79.372723034038
1998	79.2159470492966
1999	78.77619612157321
2000	77.75768360528419
2001	77.52637435589305
2002	77.27755576824573
2003	77.5672010320603
2004	77.75624389955068
2005	78.02610649135997
2006	77.96730004084861
2007	78.09789447862151
2008	77.98241011718166