Year	% of total
1990	6.789393628573629
1991	6.897596110089794
1992	6.751400795192974
1993	6.837529355160135
1994	6.711151139406878
1995	6.5317731469674465
1996	6.618384074844774
1997	6.849059294881131
1998	6.829582878021687
1999	6.874799202731572
2000	7.283988153558093
2001	7.292798530432045
2002	7.157535524609596
2003	7.187030082554349
2004	7.12418665837637
2005	7.148677399161772
2006	7.221395410351571
2007	7.25547266506256
2008	7.3651664244378265