Year	% of total
1990	64.73668512943581
1991	63.989701630887915
1992	63.408508192453866
1993	62.727150353719836
1994	63.01800108668254
1995	62.963404828373484
1996	62.91330670594145
1997	62.84622737759359
1998	63.50493390673648
1999	63.14263704855268
2000	63.024947297884346
2001	61.788031598916795
2002	62.192376998145036
2003	62.34752356908701
2004	62.98060264148656
2005	63.421735430948814
2006	62.48205916840607
2007	62.621332661670536
2008	62.488325573599276