Year	% of total
1990	63.348187171696296
1991	63.225804647268774
1992	61.37948361753946
1993	61.134594940445055
1994	60.31122400799
1995	59.715854543200955
1996	59.395674160464765
1997	60.16645994427703
1998	64.57163487059363
1999	67.01010482670664
2000	66.2451972857173
2001	65.9251022942902
2002	67.1269281074274
2003	66.699470959648
2004	66.70058943689682
2005	66.5136731677294
2006	68.29178359634012
2007	68.76107691836249
2008	71.18823212256991