Year	% of total
1990	73.09650877763887
1991	71.48831067660014
1992	70.54934995244778
1993	69.6671479206427
1994	69.33682195222849
1995	69.27912783597084
1996	68.84453804670778
1997	68.39275839369391
1998	68.54392977097902
1999	68.48465015734598
2000	68.18593550392241
2001	67.35771985419686
2002	67.49285104593794
2003	67.67051139513536
2004	67.88982256507002
2005	68.31757299723022
2006	67.87031336118201
2007	67.97685734695023
2008	68.03277895438139