Year	% of total
1990	60.573687213084256
1991	60.195896839803176
1992	58.52138876102781
1993	58.502688820336445
1994	57.768666352279965
1995	57.44719553380649
1996	57.222608714342485
1997	57.76367403249582
1998	63.18318830985108
1999	66.34068041952143
2000	66.07524280220923
2001	65.26564853900578
2002	66.25672425115548
2003	66.23025021102345
2004	66.34166267300594
2005	66.21084185646352
2006	67.99904647168458
2007	68.3751318347172
2008	70.1615587511876