Year	% of total
1990	8.516676753658373
1991	8.494850361561669
1992	8.256964661121227
1993	7.768351120773955
1994	7.466762673720349
1995	7.146575245485551
1996	6.688035491113834
1997	6.3485995771937676
1998	5.854652022137597
1999	5.593567425092889
2000	8.120087942322764
2001	8.36443712524568
2002	8.368362456844093
2003	8.622901900736876
2004	8.484019952049243
2005	8.556003332170569
2006	8.861923201321341
2007	9.016385179935416
2008	9.436277031656976