Year	% of total
1990	57.715949700139234
1991	56.90604975430036
1992	56.22057792235832
1993	55.333278164341365
1994	54.93046920988498
1995	55.76795702343079
1996	55.91195639733506
1997	56.79268743846772
1998	58.716439105452274
1999	59.532047638910235
2000	60.12979739256761
2001	59.08849185198769
2002	59.301843605204205
2003	58.66840927332747
2004	58.00532870172982
2005	58.30038215921173
2006	57.53648864431054
2007	58.114156381812016
2008	58.14420177167776